Problem Analysis #33

1014.52s
106,539 toks
Problem Statement

Let f(x)f(x) be a cubic function whose leading coefficient is positive, and let tt be a real number. Defineg(x)={f(x)(x<t),f(x)(xt),g(x) = \begin{cases}-f(x) & (x < t), \\[4pt]f(x) & (x \geq t),\end{cases}so that gg is continuous on the entire real line and satisfies the following conditions.\begin{center}\fbox{\begin{minipage}{0.9\textwidth}(A) For every real number aa, the limitlimxa+g(x)x(x2)\displaystyle\lim_{x \to a^+} \dfrac{g(x)}{x(x-2)}exists.KOR-CSAT-(B) The set of natural numbers mm for whichlimxm+g(x)x(x2)\displaystyle\lim_{x \to m^+} \dfrac{g(x)}{x(x-2)}is negative is{g(1),72g(1)}.\left\{g(-1), -\dfrac{7}{2}g(1)\right\}.\end{minipage}}\end{center}Assuming that g(1)eq72g(1)g(-1) eq -\dfrac{7}{2}g(1), compute g(5)g(-5). [4 points]\

Ground Truth
65
Execution Trace
Reasoning Process

Identify Goal: Find (g(-5)) given the conditions.

Knowns & Constraints:

  • (f(x)) is a cubic with positive leading coefficient.
  • (g(x) = \begin{cases} -f(x), & x < t \ f(x), x \ge t \end{cases})
  • (g) is continuous on (\mathbb{R}) ⇒ (f(t)=0).
  • (A) For every real (a), (\lim_{x\to a^+} \frac{g(x)}{x(x-2)}) exists (finite).
  • (B) The set of natural numbers (m) for which (\lim_{x\to m^+} \frac{g(x)}{x(x-2)},)) is negative is ({g(-1),;-\frac{7}{2}g(1)}).
  • (g(-1) \neq -\frac{7}{2}g(1)).

Step 1: Use (A) to deduce (g(0)=0) and (g(2)=0).
Because the right‑hand limits at (a=0) and (a= in response to denominator zeros require zeros of the numerator.

Since zeros of (g) are exactly zeros of (f) (because (g(x)=\pm f(x))), we have (f(0)=0) and (f(2)=0).
Write (f(x)=Ax(x-2)(x-r)) with (A>0) and real (r).

Step 2: Express (g(1), g(-1)) in terms of (A,r) and the splitting point (t) (where (t) is the chosen root of (f) used in the definition).
Three possibilities for (t): (0,;2,;r).
Compute:

  • If (t=0):
    (g(1)=A(r-1),\qquad g(-1)=3A(1+r).)

  • If (t=2):
    (g(1)=A(1-r),\qquad g(-1)=3A(1+r).)

  • If (t=r):
    (g(1)=\begin{cases} A(r-1), & r\le 1 \ A(1-r), & r>1 \end{cases}) , (g(-1)=\begin{cases} -3A(1+r), & r\le -1 \ 3A(1+r), & r>-1 \end{cases})

Step 3: Condition (B) gives two numbers: (Y=g(-1)) and (M=-\frac{7}{2}g(1)).
Both must be natural numbers (positive integers) and exactly the values of (m) for which (\lim_{x\to m^+}\frac{g(x)}{x(x-2)}<0).

Step 4: Analyze the sign of (L_m=\lim_{x\to m^+}\frac{g(x)}{x(x-2)}}).
For integer (m\ge1), one finds
[ L_m = A;\eta(m);(m-r), ]
where (\eta(m)= -1) if (equiv,m<t) and (\eta(m)=1) if (m\ge t) (with the understanding that for (m=t) the limit from the right uses (\eta=1)).
Thus (L_m<0) precisely when (m) lies strictly between (r) and (t) if (r<t), or when (t\le m<r) if (r>t).

Therefore the set of integers (m) with (L_m<0) is either ((r,t)\cap\mathbb{Z}) (if (r<t)) or ([t,;r)\cap\mathbb{Z}) (if (r>t)); if (r=t) it is empty.

Step 5: The set ({Y,M}) must equal this set, which therefore contains exactly two consecutive integers.
We test each possible (t).

  • (t=0): Then (r\in(-1,1)) from positivity of (Y) and negativity of (g(1)).
    Here (r<t) or (r>t)? Since (t=0) and (r\in(-1,1)), we have either (r<0) (giving (r<t)) → negative (m) are none (since (r<m<0) yields no positive (m)), or (0<r<1) (giving (r>t)) → negative ( M) are (m) with (0\le m<r). For (0<r<1) this gives no positive (m). Hence at most one negative (L_m) can occur, never two. So (t=0) impossible.

  • (t=r): Then no (m) gives (L_m<0). Cannot have two.

  • (t=2): Then from step 1 we need (r>1) (so that (g(1)<0)).

    • If (1<r<2), then (r<t) → negative (m) are none.
    • If (r=2), then (r=t) → no negative (m).
    • If (2<r<3), then (r>t) → negative (m) are (m=2) only.
    • If (r=3), then negative (m) are (m=2) only.
    • If (3<r<4), then negative (m) are (m=2,3) (two numbers).
    • If (r=4), negative (m) are (m=2,3) (since (m<4) gives (m=2,3)).
    • If (r>4), three or more negatives.

    Hence to have exactly two negatives we need (r\in(3,4]\setminus{3}) i.e. (r\in(3,4]) (with (r=3) excluded). In particular (r\in(3,4)) or (r=4).

Step 6: Impose that the two negative indices are exactly (Y) and (M). Since the negatives are (2) and (3) (in either order), we have ({Y,M}={2,3}).

With (t=2) we have
[ Y=3A(1+r),\qquad M=\frac{7A}{2}(r-1). ]
Set ({3A(1+r),,\frac{7A}{2}(r-1)} = {2,3}).

Solve the two possibilities:

  1. (3A(1+r)=2,;\frac{7A}{2}(r-1)=3) leads to (r=-8) (contradicts (r>3)).
  2. (3A(1+r)=3,;\frac{7A}{2}(r-1)=2) yields (A(1+r)=1) and (\frac{7}{2}A(r-1)=2).
    From the first, (A=\frac{1}{1+r}). Substitute into the second:
    [ \frac{7}{2}\cdot\frac{1}{1+r}\cdot(r-1)=2 \quad\Longrightarrow\quad 7(r-1)=4(1+r);\Longrightarrow;7r-7=4+4r;\Longrightarrow;3r=11;\Long\rightarrow;r=\frac{11}{3}. ]
    Then (A=\frac{1}{1+11/3}=\frac{3}{14}).
    Indeed (r=11/3\in(3,4)) and (Y=3), (M=2). Also (g(-1)=3\neq2) and (g(1)=A(1-r)=-\frac{4}{7}), so (M=-\frac{7}{2}\cdot(-\frac{4}{7})=2). Conditions satisfied.

Thus the unique parameters are (A=\frac{3}{14},;r=\frac{11}{3},;t=2).

Step 7: Compute (g(-5)). Since (-5<t=2), (g(-5)=-f(-5)).
[ f(x)=\frac{3}{14},x(x-2)\left(x-\frac{11}{3}\right). ]
Then
[ f(-5)=\frac{3}{14}\cdot(-5)\cdot(-7)\cdot\left(-5-\frac{11}{3}\right) = \frac{Strictly: -5\cdot(-7)=35,\quad -5-\frac{11}{3}=-\frac{26}{3}. ]
So (f(-5)=\frac{3}{14}\cdot 35\cdot\left(-\frac{26}{3}\right)=-\frac{3\cdot35\cdot26}{14\cdot3}=-\frac{2730}{42}?) Let's recalc carefully:

[ f(-5)=\frac{3}{14}\times(-5)\times(-7)\times\left(-\frac{26}{3}\right). ]
Compute step: ((-5)\times(-7)=35). So
[ f(-5)=\frac{3}{14}\times 35 \times \left(-\frac{26}{3}\right) = \frac{3\times35\times(-26)}{14\times3} = \frac{35\times(-26)}{14} = -\frac{910}{14} = -65. ]
Thus (f(-5) = -65). Hence (g(-5) = -f(-5) = 65).

Answer: (\boxed{65})

Reasoning Process

Answer: \boxed{65}

Reasoning Process

[THOUGHT] We need to find t, r, A such that the set of m with L(m)<0 equals {g(-1), -7/2 g(1)} (both natural numbers, consecutive), and g(-1) ≠ -7/2 g(1). Also f(x) = A x (x-2)(x - r) with A>0, t ∈ {0,2,r}, and g defined accordingly.

We have L(m) = s_m * A (m - r) where s_m = -1 if m < t, +1 if m ≥ t. And L(m) < 0 ↔ s_m (m - r) < 0.

Given this, the set of m with L(m)<0 is a set of consecutive integers as described. Since we need exactly two such m, we have two cases: either r < t and (r, t) contains exactly two integers; or r > t and [t, r) contains exactly two integers.

Also g(-1) and g(1) expressed in terms of A, r, t.

Compute f(1) = A * 1 * (1-2)(1 - r) = A * 1 * (-1) * (1 - r) = -A (1 - r) = A (r - 1). Actually compute: (1)(-1)(1 - r) = (-1)(1 - r) = -(1 - r) = r - 1. So f(1) = A (r - 1). Good.

Compute f(-1) = A * (-1) * (-1 - 2) * (-1 - r) = A * (-1) * (-3) * (-(1 + r))? Let's do: (-1) * (-3) = 3, then 3 * (-(1+r))? Wait: (-1 - r) = -(1 + r). So product: (-1) * (-3) = 3; 3 * (-(1+r)) = -3(1+r). So f(-1) = -3A (1 + r). Let's verify: f(-1) = A*(-1)(-3)(-1 - r) = A*(-1)(-3)(-(1+?)). Actually compute step by step: x = -1, (x) = -1, (x-2) = -3, (x - r) = -1 - r = -(1 + r). So product = (-1)(-3)(-(1+r)) = (3)*(-(1+r)) = -3(1+r). So f(-1) = -3A (1 + r). Yes.

Now g(1) = ε * f(1) where ε = -1 if 1 < t? Actually if t > 1 then g(1) = -f(1); if t ≤ 1 then g(1) = f(1). So ε = +1 if t ≤ 1, ε = -1 if t > 1.

Similarly, g(-1) = δ * f(-1) with δ = -1 if -1 < t (i.eScenario: if t > -1 then g(-1) = -f(-1); if t ≤ -1 then g(-1) = f(-1). But t is a root of cubic; could be less than -1? Possibly if r is < -1, then t = r could be < -1. If t = 0 or 2, then t > -1. So generally t is ≥ -something? We'll consider.

Thus: g(1) = η1 * A (r - 1) where η1 = +1 if t ≤ 1, η1 = -1 if t > Gen. g(-1) = η2 * (-3A(1 + r))? Wait f(-1) = -3A(1+r). So g(-1) = δ * (-3A(1+r)) where δ = +1 if t ≤ -1? Actually if t ≤ -1, then for x=-1 ≥ t? No, g(x)=f(x) if x ≥ t. So if t ≤ -1, then for x=-1, since -1 ≥ t? Actually if t ≤ -1, then -1 could be ≥ t? If t = -2, then -1 ≥ -2, yes. So g(-1) = f(-1). If t > -1, then -1 < t, so g(-1) = -f(-1). So δ = +1 if t ≤ -1; δ = -1 if t > -1.

But note: t is either 0, 2, or r. So t ≤ -1 would only happen if t = r and r ≤ -1. So that is possible. For t = 0 or 2, we have t > -1, so δ = -1, giving g(-1) = -f(-1). For t = r with r ≤ -1, δ = +1 (since t ≤ -1). If r = -1 exactly? Then t = -1, and t ≤ -1, so δ = +1? Actually if t = -1, then for x = -1, is x ≥ t? Since -1 ≥ -1, yes, so g(-1) = f(-1). So δ = +1. If t = -1, then g(-1)=f(-1). If t = r and r > -1, then δ = -1.

Thus: If t = 0 or t = 2: g(-1) = -f(-1) = -(-3A(1+r))? Wait f(-1) = -3A(1+r). So -f(-1) = 3A(1+r). So g(-1) = 3A(1+r).

If t = r and r > -1: then g(-1) = -f(-1) = 3A(1+r). If t = r and r < -1: then g(-1) = f(-1) = -3A(1+r). But if r < -1, then (1+r) is negative, so f(-1) = -3A(1+r) = -3A*(negative) = positive? Actually if r < -1, then 1+r < 0, so -3A(1+r) = -3A*(negative) = positive * A? Wait: f(-1) = -3A(1+r). If 1+r < 0, then -3A(1+r) = -3A*(negative) = positive * A? Actually -3A*(negative) = positive * 3A? Let's keep symbolic.

If t = r and r < -1: g(-1) = f(-1) = -3A(1+r). Since (1+r) is negative, -3A(1+r) = -3A*(negative) = positive? Actually -3A * (negative) = positive * 3A? Example: r=-2 => 1+r = -1 => -3A*(-1) = 3A. So g(-1) = 3A? Wait that would be positive. But anyway.

If t = r and r = -1: g(-1) = f(-1) = -3A(0) = 0, but then g(-1) = 0, which is not a natural number (natural numbers are positive integers). So r = -1 is probably not allowed because then g(-1) = 0 not natural. So r ≠ -1.

Thus for t = r, if r < -1, g(-1) = -3A(1+r) which is positive because (1+r) negative => -3A(1+r) > 0. Actually careful: f(-1) = -3A(1+r). If r < -1, then (1+r) < 0, so f(-1) = -3A*(negative) = positive A * something. So g(-1) = f(-1) > 0. So that could be a natural number possibly.

If r > -1 and r ≠ -1, then g(-1) = -f(-1) = 3A(1+r). Since 1+r > 0, that's positive.

So in all cases, g(-1) appears to be positive (except maybe if A chosen appropriately). But we need to check.

Now g(1) = η1 * A (r - _framework. Let's compute f(1) = A(r - 1). So if t ≤ 1, then g(1) = A(r - 1). If t > 1, then g(1) = -A(r - 1) = A(1 - r). So g(1) = A * ± (r - 1). Specifically:

  • If t ≤ 1: g(1) = A(r - 1)
  • If t > 1: g(1) = A(1 - r)

Now we also have -7/2 g(1) must be a natural number. So g(1) must be even/?? Actually -7/2 g(1) ∈ ℕ. Since natural numbers are positive, we need -7/2 g(1) > 0 => g(1) < 0. Because -7/2 * positive = negative; -7/2 * negative = positive. Wait: If g(1) is positive, then -7/2 g(1) is negative, which is not a natural number (unless we consider 0? No). So we require -7/2 g(1) > 0 => g(1) < 0. So g(1) must be negative. And then -7/2 g(1) = (7/2)(-g(1)) > 0. So g(1) negative. So g(1) must be a negative number such that (7/2)(-g(1)) is integer. Equivalently, -g(1) must be even/?? Actually let g(1) = -k where k>0, then -7/2 g(1) = -7/2 * (-k) = -7k/2? Wait: If g(1) = -k, k>0, then -7/2 * (-k) = (7k)/2. So we need (7k)/2 integer. So k must be even: k = 2m, then (7*2m)/2 = 7m, integer. So g(1) = -2m for some positive integer m, and then -7/2 g(1) = 7m, which is a positive integer. So -7/2 g(1) = 7m, and g(1) = -2m. So g(1) is a negative even integer.

Thus g(1) is a negative even integer. And -7/2 g(1) = 7m = (7/2)(-g(1)) is a positive integer. So g(-1) and 7m are the two numbers (consecutive natural numbers). So we have two numbers: p = g(-1) and q = -7/2 g(1) = 7m. They are consecutive natural numbers. So {p, q} = {g(-1), 7m} are two consecutive positive integers.

Now g(-1) is also a positive integer. And we have relation between g(-1) and g(1) via A, r, t.

Now we also have constraints from the fact that the set of m with L(m)<0 are exactly those two numbers. So that set is {k, k+1} for some integer k ≥ 1? Possibly includes 1? Could be {1,2} or {2,3}, etc. We'll determine later.

Now we also have that the two numbers g(-1) and -7/2 g(1) are exactly those two m's. So the m values that yield L(m)<0 are exactly p and q. So p and q are the two consecutive integers in the set described.

Thus we need to find t, r, A such that L(m)<0 exactly for m = p and m = p+1, where p = g(-1) and q = p+1, or vice versa? Actually the set is {g(-1), -7/2 g(1)} and they are distinct. So the two numbers are g(-1) and -7/2 g(1). They are consecutive. So either g(-1) = k and -7/2 g(1) = k+1, or g(-1) = k+1 and -7/2 g(1) = k.

Now we also have expressions for g(-1) and g(1) in terms of A, r, t.

We also have that p and q are exactly the m values where L(m)<0. So the condition L(m)<0 is equivalent to m ∈ {p, q}. That gives us two equations: For m = p and m = q, L(m) < 0; for all other m (natural numbers), L(m) > 0 (or maybe =0? But likely >0). However, L(m) could be zero if m = r or m = t? But L(m) = s_m A (m - r). Zero if m = r. But m are integers, r may not be integer. So likely no m yields zero because r is not integer (or if r is integer, then L(r)=0, but then the condition says L(m) < 0 for exactly two m, so r cannot be integer? Possibly r could be integer but then L(r)=0, not negative, so it wouldn't be in the set. That's fine. So we just need exactly two m with negative L(m). So we can work with the derived condition: L(m)<0 iff (m < t and m > r) or (m ≥ t and m < r). So the set of integers satisfying this is either (if r < t) integers m with r < m < t, or (if r > t) integers m with t ≤ m < r. Since there are exactly two such integers, we have two cases.

Case 1: r < t. Then the set is {m ∈ ℤ : r < m < t}. Since there are exactly two integers in this interval, and it's an open interval, the two integers must be consecutive. So there exists integer k such that {k, k+1} = {m : r < m < t}. So we have r < k < k+1 < t, and no other integers between. So that means r ≤ k and k+1 ≤ t-? Actually r < k and k+1 ≤ t? But since they are the only integers strictly between r and t, we must have r ≤ k and k+1 ≤ t, and either r > k-1 (i.e., r > k-1) or if r is between k-1 and k? Let's be precise: For open interval (r, t) to contain exactly two integers, say k and k+1, we need r ∈ [k-1, k) and t ∈ (k+1, k+2]? Actually more systematically: The integers strictly between r and t are those m with r < m < t. For there to be exactly two integers, the interval (r, t) must contain exactly two integers. That means there exists integer k such that r < k < k+1 < t, and no other integers. So we need r < k and k+1 < t, and additionally r ≥ k-1? Not necessarily; if r is less than k, but the next integer is k, that's fine. However, if r ≤ k-1, then k-1 could also be > r? Actually if r ≤ k-1, then k-1 > r, but we need k-1 not to be satisfy k-1 > r? Wait we need that no integer m other than k, k+1 satisfy r < m < t. If r ≤ k-1, then k-1 > r (since k-1 ≥ r? Actually if r ≤ k-1, it's possible that k-1 > r, unless r = k-1? If r < k-1, then k-1 > r. So then k-1 would also be > r and < t? Not necessarily, because we need m < t. If t > k+1, then k-1 might be less than t as well. So to ensure only k and k+1, we need that r < k and k+1 < t, and additionally r ≥ k-1? Let's test: Suppose r = 0.2, t = 4.5. Then integers strictly between 0.2 and 4.5 are 1,2,3,4 => four integers. So to have exactly two, the length of interval must be such that it spans exactly two integers. That means r is in (k-1, k] and t is in (k+1, k+2)? Actually need exactly two integers: k and k+ abortion. Let’s denote the smallest integer > r is m0 = floor(r)+1. The largest integer < t is m1 = t-? Actually the integers in (r, t) are those m such that m > r and m < t. The count is max(0, floor(t-1) - floor(r) )? Actually number of integers m with r < m < t is: if t-1 > r, count = max(0, floor(t-1) - floor(r) ). But anyway, for exactly two, we need floor(t-1) - floor(r) = 2, and also r not integer? Actually if r is integer, then r < m means m ≥ r+1, so the first candidate is r+1. So the count is max(0, floor(t-1) - (r) ). If r integer, floor(r) = r, but then floor(r) = r, but since m > r, the smallest integer is r+1. So the count = max(0, floor(t-1) - (r) )? Actually number of integers m with r < m < t = max(0, floor(t-1) - r). Because if t-1 > r, then floor(t-1) is greatest integer ≤ t-1. Then integers m such that r < m ≤ floor(t-1) are counted? Wait careful: m integer, r < m < t. This is equivalent to m ∈ { floor(r)+1, floor(r)+2, ..., ceil(t)-1 }? But easier: The count = max(0, ceil(t-1) - ceil(r)? Not great.

But we can handle by considering the two scenarios: r < t and the integers between are consecutive. So we have r < k < k+1 < t. That's necessary and sufficient provided there are no other integers in between. That means r ≤ k and k+1 ≤ t, and also r > k-1? Actually if r ≤ k-1, then k-1 could also be > r? If r ≤ k-1, then k-1 > r? Not necessarily; if r = k-1 exactly, then r < k? r = k-1 < k, but m must be > r. Since m > k-1, the integer k-1 is not > r because it's equal to r? Actually if r = k-1, then r = k-1, then m > k-1 means m ≥ k, so k-1 is not > r. So that's fine. So if r = k-1, then the integers > r are k, k+1, ... So if also t > k+1, then there would be more than two integers. So we need t ≤ k+2? Actually we need exactly two integers: k and k+1. That means we need r < k and k+1 < t, and additionally there is no integer k-1 satisfying r < k-1? But k-1 ≤ r? Because if r < k-1, then k-1 > r, so k-1 would be in (r, t) provided k-1 < t. Since k-1 < k < t, that would add an extra integer. So we must avoid that. So we need r ≥ k- and this ensures that no integer m ≤ k-2? Actually the condition is: the largest integer less than or equal to r? Let's think: For integer m to be > r, the smallest possible m is floor(r)+1. For there to be exactly two integers, we need floor(r)+1 = k and floor(r)+2 = k+1 < t, and also floor(r)+3 ≥ t (otherwise k+2 would also be < t). So we need floor(r)+2 < t < floor(r)+4? Let's do systematically:

Let n = floor(r) if r not integer; if r is integer, floor(r) = r. But r may not be integer. Let a = floor(r). Then integers > r start at m0 = a+1. The integers m that satisfy r < m < t are m = a+1, a+2, ... up to floor(t-1). So count = max(0, floor(t-1) - a). For exactly two, we need floor(t-1) - a = 2, and also ensure that r is not integer? Actually if r is integer, then a = r, and the smallest integer > r is r+1. So count = floor(t-1) - r = 2. So that would be two integers: r+1 and r+2. So that requires r+2 < t ≤ r+3? Actually floor(t-1) = r+2 means r+2 ≤ t-1? Wait floor(t-1) = r+2 means r+2 ≤ t-1 < r+3 => t ∈ [r+3, r+4)? No, let's solve: floor(t-1) = r+2. Since floor(t-1) = r+2 implies r+2 ≤ t-1 < r+3 => r+3 ≤ t < r+4. But we need also that t > r+2? Actually we need that the integers r+1 and r+2 are both < t. Since t > r+2? Because for integer r+2 to be < t, we need t > r+2. And we also need that no integer r+3 is < t, so t ≤ r+3? Because if t > r+3, then r+3 < t, then r+3 would be another integer in (r, t). So we need t ∈ (r+2, r+3]? Actually if t > r+2, then r+2 < t, so r+2 is in (r, t) provided r+2 > r which is true. If t > r+3, then r+3 < t, so r+3 is also in (r, t) if r+3 > r, which it is. So to have exactly integers r+1 and r+ depression, we need t ∈ (r+2, r+3] maybe? Let's do systematically:

We want exactly two integers m satisfying r < m < t. Let those integers be p and p+1. Then we need r < p and p+1 < t, and also r ≥ p-1? Because if r < p-1, then p-1 would also satisfy r < p-1? Actually if r < p-1, then p-1 > r, so p-1 would be in (r, t) provided p-1 < t. Since p-1 < p < t, yes p-1 would also be in (r, t). So to avoid that, we need r ≥ p-1. But since p-1 < p, if r = p-1 exactly, then p-1 is not > r (since p-1 = r, not >). So that's okay. So we require r ∈ [p-1, p). Similarly, to ensure no integer > p+1 is less than t, we need t ≤ p+2? Because if t > p+2, then p+2 < t, so p+2 would be in (r, t). So we need t ≤ p+2. But also we need p+1 < t (since p+1 < t to have p+1 in the interval). So we need p+1 < t ≤ p+2. So t ∈ (p+1, p+2]. Additionally, we need r < p and r ≥ p-1? Actually r < p (since p > r). And also r ≥ p-1? Because if r < p-1, then p-1 > r, so p-1 would be in (r, t) if p-1 < t. Since p-1 < p < t, that would add p-1. So to avoid p-1, we need r ≥ p-1. So r ∈ [p-1, p). So in case r < t, we have r ∈ [p-1, p) and t ∈ (p+1, p+2] for some integer p. And the two integers are p and p+1. Note p is integer; could be any integer (could be negative? But m are natural numbers (positive). So p and p+1 are positive. So p ≥ 1.

Thus for case r < t, the set of m with L(m)<0 is {p, p+1} where p = floor(r)+1? Actually p = floor(r)+1? Since r ∈ [p-1, p), floor(r) = p-1, so p = floor(r)+1. And t ∈ (p+1, p+2] (if t not integer) or t ∈ (p+1, p+2]? But t could be exactly p+2? If t = p+2, then integers m with r < m < t: Since r < p < p+1 < p+2 = t? Wait if t = p+2, then m < t means m ≤ p+1? Since m integer, m ≤ p+1. And m > r. Since r ≥ p-Atmospheric, the integers > r are p and p+1 (since p > r, p+1 > r, and p+2 = t not < t). So if t = p+2, then m < t excludes m = p+2, so m = p, p+1 are included. So t can equal p+ case? But we also need t > p+1? Because t must be > p+1? Actually for m = p+1 to be < t, we need t > p+1. So t > p+1. And for m = p+2 not to be included, we need t ≤ p+2. So t ∈ (p+1, p+2]. So yes.

Thus in case r < t, we have r ∈ [p-1, p) and t ∈ (p+1, p+2] for some integer p ≥ 1. And the two m's are p and p+1.

Now case 2: r > t. Then the set of m with L(m)<0 is { m integer : t ≤ m < r }. This is an interval of integers from t (if t integer) or ceil(t) to r-1 (if r integer) or floor(r) if r not integer. For this set to contain exactly two consecutive integers, say q and q+1, we need that t ≤ q and q+1 < r, and also t > q-1? Actually we need exactly these two integers. That means the smallest integer m in the set is q, and the largest is q+1. So we need ceil(t) = q and floor(r-ε) = q+1? More precisely, if t is not integer, then the smallest integer ≥ t is ceil(t). So we need ceil(t) = q. And if r is not integer, then the largest integer < r is floor(r). So we need floor(r) = q+1. So then the integers are q and q+1. If r is integer, then m < r means m ≤ r-1, and the set includes t ≤ m ≤ r-1? Actually if r is integer, then condition m < r means m ≤ r-1. So the largest integer is r-1. For the set to be {q, q+1}, we need q = ceil(t) and q+1 = r-1? That would mean r = q+2. And also t > q-1? Let's derive generally.

We need the set S = { m ∈ ℤ : t ≤ m < r } to have exactly two integers. Let those integers be q and q+1. So we need:

  • q is the smallest integer in S, so q ≥ t and q-1 < t? Actually q must satisfy q ≥ t and q-1 < t (otherwise if q-1 ≥ t, then q-1 would also be in S). So we need t ∈ (q-1, q] (if t integer, then t ≤ q? Wait if t = q, then q ≥ t, and q-1 = q-1 < t because t = q > q-1, so q-1 < t holds. So that works. So condition is t ∈ (q-1, q] (including q). But careful: If t = q exactly, then m ≥ t includes m = q, so that's fine. If t is in (q-1, q), then ceil(t) = q? Actually if t ∈ (q-1, q), then ceil(t) = q (since smallest integer ≥ t is q). So indeed the smallest m in S is q. So condition for q being the minimum is t ∈ (q-1, q].

Now the maximum m in S is the largest integer less than r. So we need that maximum = q+1. So we need q+1 < r ≤ q+2? Because if r > q+2, then q+2 ≤ floor(r)? Actually if r > q+2, then q+fact: if r ∈ (q+1, q+2], then floor(r) = q+1 (if r ≤ q+2) or if r = q+2 exactly, then r is integer? If r = q+2 exactly, then m < r means m ≤ q+1, so maximum is q+1. If r ∈ (q+1, q+2), then floor(r) = q+1, so maximum is q+1. If r = q+1, then m < q+1 => m ≤ q, so maximum would be q, not q+1. So we need r > q+1. Also to avoid including q+2, we need r ≤ q+2. If r > q+2, then q+ = q+2 would be included if q+2 < r? Actually if r > q+2, then q+2 < r (if r > q+2), then q+2 is an integer less than r, so it would be in S, giving at least three integers. So we need r ≤ q+2. But also r > q+1 to have q+1 included. So r ∈ (q+1, q+2]. If r = q+2 exactly, it's okay; if r is between q+1 and q+2, it's also okay. Also note that r could equal q+2 exactly, and then the set is { m integer: t ≤ m < q+2 } = if t > q-1, then includes q and q+1? Check: If r = q+2, then m < r means m ≤ q+1. So the set includes q and q+1 provided t ≤ q. But we need t > q-1. So t could be in (q-1, q] or maybe t = q? If t = q, then set = {q, q+1}? Actually if t = q, then condition m ≥ q, so includes q, q+1. That's two integers. But then we would have q and q+1, which matches. However, if t = q, then t is integer. But t is either 0, protesting. Thus for case r > t, we have t ∈ (q-1, q] (i.e., t ∈ (q-1, q] maybe inclusive at q), and r ∈ (q+1, q+2]. And the two integers are q and q+1.

But careful: In case r > t, the set is { m : t ≤ m < r }. For there to be exactly two integers, we need that the smallest integer ≥ t is q, and the largest integer < r is q+1. So we need ceil(t) = q and floor(r - ε) = q+1 (i.e., floor(r) = q+1 if r not integer; if r is integer, then the largest integer < r is r-1, so we need r-1 = q+1 => r = q+2; and if r is integer, then r = q+2 exactly, and also r > q+1, so that works). So in all cases, we have t ∈ (q-1, q] and r ∈ (q+1, q+2] (with r possibly equal to q+2). And the two integers are q and q+1.

But note: In case r < t, we had the two integers also consecutive, but the condition was r ∈ [q-1, q) and t ∈ (q+1, q+2]? Actually we got r ∈ [p-1, p) and t ∈ (p+1, p+2] and the two integers are p and p+1. So both cases give the same pattern: the two integers are some consecutive integers k and k+1. In case r < t, we have r < k+1? Wait: we set p = k, then r ∈ [k-1, k) and t ∈ (k+1, k+2]. In case r > t, we have t ∈ (k-1, k] and r ∈ (k+1, k+2]. So essentially r and t are on opposite sides of the interval (k, k+1)? Actually in case r < t, r is less than the interval (r,t) which contains the two integers; r is below the interval, t is above. In case r > t, t is below the interval, r is above. So r and t lie on opposite sides of the two integers.

Now we also have expressions for g(-1) and g(1) in terms of A, r, t. And we have the specific values g(-1) = p or p+1, and -7/2 g(1) = the other one.

Thus we need to consider the three possibilities for t: 0, 2, or r.

We also have the condition that g(-1) and -7/2 g(1) are positive integers, and they are the two consecutive integers p and p+1.

Now we need to find A, r, and which case (r < t or r > t) and t, such that these hold.

Also note: The condition (A) we already used implicitly? We used to deduce f(0)=0, f(2)=0. That's fine. Also we used that L(m) = s_m A (m - r) for m integer, but that formula assumed m ≠ 0,2. For m=2, we also have the same expression? Yes, we argued that for m=2, L(2) = s_2 * A (2 - r) because f(x)/(x(x-2)) = A(x - r) for x≠0,2, so limit as x→2+ is A(2 - r). So it's consistent. So our analysis for L(m) sign is correct for all natural m (including 2) provided m ≠ 0, m=0 not natural. So we are fine.

Now we need to find p = one of the numbers? Actually we have two specific numbers: g(-1) and -7/2 g(1). They are consecutive integers. So we need to find integer values for g(-1) and g(1) in terms of A, r, t.

Let's compute g(1) and g(-1) explicitly.

Recall:

f(1) = A (r - 1) f(-1) = -3A (1 + r)

Now g(1) =

  • if t ≤ 1: g(1) = f(1) = A(r - 1)
  • if t > 1: g(1) = -f(1) = A(1 - r)

g(-1) =

  • if t ≤ -1: g(-1) = f(-1) = -3A(1 + r)
  • if t > -1: g(-1) = -f(-1) = 3A(1 + r)

Since t is either 0, 2, or r. t = 0 or 2 are both > -1. So for t = 0 or 2, we have t > -1, so g(-1) = 3A(1 + r). For t = r, we need to compare r to -1. If r > -1, then t = r > -1, so g(-1) = 3A(1 + r). If r < -1, then t = r < -1, so g(-1) = -3A(1 + r). If r = -1, then t = -1, and then g(-1) = f(-1) = -3A(0)=0, not natural, so r ≠ -1.

Thus for t = r, g(-1) = 3A(1 + r) if r > -1; = -3A(1 + r) if r < -1. Since if r < -1, then (1+r) negative, so -3A(1+r) = -3A*(negative) = positive. So g(-1) = -3A(1 + r) > 0. So we can write g(-1) = 3A |1+r|? Not exactly.

But we can treat it as g(-1) = 3A |1 + r|? Not exactly, because sign matters: For t = 0 or 2, g(-1) = 3A(1+r). For t = r and r > -1, g(-1) = 3A(1+r). For t = r and r < -1, g(-1) = -3A(1+r) (which is positive because (1+r) negative). So we can combine: g(-1) = 3A * (1+r) if t ≠ r or if t=r > -1; and g(-1) = -3A(1+r) if t=r and r < -1. But careful: If t = r and r < -1, then g(-1) = f(-1) = -3A(1+r). Since (1+r) negative, -3A(1+r) > 0. So g(-1) = -3A(1+r) = |3A(1+r)|.

Now g(1) = A(r - 1) if t ≤ 1; = A(1 - r) if t > 1.

Since t is either 0, 2, or r. For t = 0, t ≤ 1, so g(1) = A(r - 1). For t = 2, t > 1, so g(1) = A(1 - r). For t = r, if r ≤ 1, then g(1) = A(r - 1); if r > 1, then g(1) = A(1 - r).

Now note that g(1) must be negative (since -7/2 g(1) > 0). So g(1) < 0. That gives constraints.

Also -7/2 g(1) = some integer. Since g(1) negative even integer as argued? Let's verify: g(1) negative, and -7/2 g(1) integer. Write g(1) = -2k (k positive integer). Then -7/2 * (-2k) = 7k, integer. So g(1) must be an even negative integer. So g(7) is even negative integer. So g(1) = -2k, k ∈ ℕ.

Now g(-1) = either 3A(1+r) or -3A(1+r) etc. But g(-1) must be a positive integer, and also must be either p or p+1.

Now we also have A > 0. And r is real, not necessarily integer. But from the expressions, A and r must satisfy that g(1) and g(-1) are integers. Since A > 0, but A could be rational? Possibly A is determined by other constraints. However, we also have that the two m's are p and p+1, and they are exactly the m for which L(m)<0. That gives relations between r and t as derived: either (r < t and t ∈ (p+1, p+2], r ∈ [p-1, p)) or (r > t and t ∈ (p-1, p], r ∈ (p+1, p+2]).

And we also have that g(-1) and g(1) equal p and q in some order.

Thus we need to consider the three cases for t (0,2,r). Let's denote the two consecutive integers as n and n+1 (n≥1). Without loss, let’s call p = n, q = n+1. So {g(-1), -7/2 g(1)} = {n, n+1}.

Now we also have g(1) negative even integer, and -7/2 g(1) = 7k (where g(1) = -2k). So -7/2 g(1) = 7k, which must equal either n or n+1. So 7k is either n or n+1. So n or n+1 is a multiple of 7. So the set {n, n+1} contains a multiple of 7. So either n ≡ 0 mod 7 or n+1 ≡ 0 mod 7. So n = 7k or n = 7k - 1.

But also g(-1) is the other one, and g(-1) = something positive.

Now we also have g(1) = -2k.

Now we need to express g(1) in terms of A, r, t. And g(-1) similarly.

Let's enumerate cases for t.

Case I: t = 0. Then t = 0. Since t = 0 ≤ 1, so g(1) = A(r - 1). Also t > -1, so g(-1) = 3A(1 + r).

We also have the condition about the set of m with L(m)<0. Since t = 0, we can compute r relative to t. We have t = 0. The two cases for sign of (r - t) determine which scenario: if r < t (i.e., r < 0) or r > t (r > 0). Since t=0, r could be negative, zero, or positive. But r cannot be 0 because then f would have double root at 0? Actually f(x) = A x (x-2)(x - r). If r = 0, then f(x) = A x^2 (x-2), which is cubic with double root at 0. That is allowed? Possibly, but then t must be one of 0,2,r. If r=0, then t could be 0 (since 0 is a root). That's allowed. But then f(x) = A x^2 (x-2). But then the leading coefficient positive. However, we also have the condition about limit existence for all x? That should be fine. But we also have condition (A) which is about limit as x→a+ of g(x)/(x(x-2)) exists for every a. That imposes continuity of the expression? Actually we already used that to deduce f(0)=0 and f(2)=0. If r=0, f(x)=A x^2 (x-2). That still satisfies f(0)=0, f(2)=0. So it's okay. But then g(-1) and g(1) need to be natural numbers, etc. We'll see.

But note: r = 0 would make f(1) = A(0 - 1) = -A, g(1) = A(r-1) = -A, which is negative if A>0. That's okay. But then -7/2 g(1) = -A*7/2? Actually -7/2 * (-A) = (7A)/2, which would be integer only if A even/ something. But A could be rational. However, we also have g(-1) = 3A(1+0 zosta.! Actually g(-1) = 3A(1+0) = 3A. So that would be integer if A rational. But we also have that the set of m with L(m)<0 must be {g(-1), -7/2 g(1)} = {3A, (7A)/2}. And these must be consecutive integers. So 3A and (7A)/2 are consecutive integers. That would give A such that both are integers. That is a possibility, but we also have t=0, so t=0. Then the condition on r and t from the set of m: t=0. The set of m with L(m)<0 is determined by whether r < t (i.e., r<0) or r > t (r>0). Since t=0, the two cases are r<0 or r>0. If r<0, then r < t, and the set of m is those integers between r and t = (r, 0). Since t=0, the integers m with r < m < 0. Since m are natural numbers (positive), there are none because the only integer in (r,0) could be negative or zero? Natural numbers are positive (1,2,...). So there would be no natural numbers. But we need exactly two natural numbers. So r<0 cannot yield two positive integers. If r>0, then r > t, and the set of m is those with t ≤ m < r, i.e., 0 ≤ m < r (but m natural starts at 1, so m=1,2,..., up to ceil? Actually m natural: m≥1. So if r > 0, the set of m with 0 ≤ m < r? Wait condition: t ≤ m < r, with t=0. So m ≥ 0. But m natural means m≥1, so effectively m = 1,2,..., floor(r) if r not integer, or up to r-1 if integer. So the number of natural numbers in that interval is max(0, floor(r-ε) - 0? Actually number of positive integers m with m < r and m ≥ 1. So if r > 1, then there are floor(r) - 0? Actually count = number of integers m such that 1 ≤ m < r. That's max(0, floor(r-1) - 1 + 1?) Let's compute: m ∈ ℤ, 1 ≤ m ≤ ceil(r)-1? Better: m ∈ ℕ, m < r. So count = max(0, ⌈r⌉ - 1) if r not integer? Actually if r = 3.2, then m can be 1,2,3 → three numbers. That's floor(r) if r not integer? floor(3.2)=3, yes. If r = 3 exactly, then m < 3 → m=1,2 → two numbers. So count = floor(r) if r not integer; count = r-1 if r integer. So the number of m is either floor(r) (if r not integer) or r-1 (if r integer). For this count to be exactly 2, we need either r ∈ (2,3) giving floor(r)=2 → r ∈ (2,3) yields m=1,2? Wait floor(r)=2 for 2<r<3, but r must be >1? Actually if r=2.5, then m=1,2 → two numbers. If r=3 exactly, then m=1,2 → two numbers? Actually if r=3, then m < 3, m=1,2 → two numbers. So r ∈ (2,3] gives exactly two integers? But careful: if r ∈ (2,3), floor(r)=2, so m=1,2 → two integers. If r=3, floor(3)=3, but m < 3 gives m=1,2 → still two integers. So r ∈ (2,3] yields exactly two integers (1 and 2). If r ∈ (1,2], floor(r)=1? For r=1.5, floor=1 → m=1 → one integer. So not enough. If r ∈ (3,4), floor(r)=3 → m=1,2,3 → three integers. So for exactly two integers, we need r ∈ (2,3]. But also need t=0 ≤ m. So t=0, r>0. So r ∈ (2,3]? Actually if r ∈ (2,3], then m=1,2 (since m< r, and m≥1). That's two integers. If r=2.5, m=1,2. If r=3, m=1,2. If r just above 2, m=1,2. If r=2, then m < 2 → m=1 only, one integer. So r must be >2? Actually for r=2, m<2 gives m=1 only. So r>2. So r ∈ (2,3] gives exactly two integers? Wait r=3 gives m=1,2 (two integers). r=2.2 gives m=1,2? Since 2 < 2.2, so m=2 is <2.2, so m=2 is included; m=1 also. So yes two integers. So r ∈ (2,3] yields exactly two integers (1 and 2). But we also need that the two integers are exactly 1 and 2. So p=1, p+1=2. So the set of m with L(m)<0 would be {1,2}. That would mean g(-1) and -7/2 g(1) are {1,2} in some order.

But we also have g(1) = A(r - 1). Since r > 2, r - 1 > 1, so g(1) > A. But g(1) must be negative even integer. If r > 2, r - 1 > 1, so A(r-1) positive for A>0. That would make g(1) positive. But we need g(1) negative. Contradiction. So t=0 with r>0 fails because g(1) becomes positive if r>1. Wait check: g(1) = A(r-1). If r>1, then r-1 >0 => g(1) >0. But we need g(1) negative. So that's impossible. If r<0, then g(1) = A(r-1) is negative because r-1 < -1? Actually if r<0, r-1 < -1, so negative. So g(1) negative. Good. So r<0 case gives g(1) negative. But as we argued, if r<0, then r < t (since t=0). Then the set of m with L(m)<0 is integers m such that r < m < t = 0. Since m are natural numbers (positive), there are no such m because the only integer between r (negative) and 0 is possibly -? Actually if r < -1, then integers m such that r < m < 0 could be negative integers like -1? But natural numbers are positive, so none. If r is between -1 and 0, say r=-0.5, then integers m with -0.5 < m < 0? None. So indeed no natural numbers. So the set would be empty, not two. So t=0 cannot yield exactly two natural numbers with L(m)<0. Therefore t=0 is impossible.

Thus t ≠ 0.

Case II: t = 2. Then t = 2. Since t=2 >1, we have g(1) = A(1 - r). Also t > -1, so g(-1) = 3A(1 + r) (since t > -1). So g(1) = A(1 - r) = -A(r - 1). Since we need g(1) < 0, we need 1 - r < 0 => r > 1. So r > 1. Also g(1) negative even integer? So A(1 - r) = -A(r-1) must be negative even integer. Since A>0, (r-1) > 0, so -A(r-1) is negative. So ok.

Now g(-1) = 3A(1 + r). Since r > 1, 1+r > 2, so g(-1) positive.

Now we need to determine the set of m with L(m)<0. Since t=2. Compare r to t=2. Two subcases: r < t (i.e., r < 2) or r > t (r > 2) or r = t (r=2). r=2 would give f(x) = A x (x-2)^2. That could be possible. But we need to check.

We need exactly two natural numbers m with L(m)<0. Let's analyze both subcases.

Subcase IIa: r < t, i.e., r < 2. Since we already have r > 1 from g(1) negative, we have 1 < r < 2. Then the set of m with L(m)<0 is those with r < m < t, i.e., r < m < 2. Since r > 1, the integers m satisfying 1 < m < 2? There is no integer strictly between 1 and 2. The only possible integer is 2? But m=2 is not <2. So none. So no natural numbers. So not two.

Subcase IIb: r > t, i.e., r > 2. Then the set of m with L(m)<0 is those with t ≤ m < r, i.e., 2 ≤ m < r. Since m natural numbers, m starts at 2? But m=2 is included because t ≤ m? t=2, so m=2 satisfies m ≥ t, and m < r. So m=2 is included if r > 2. Also m=3,4,... depending on r. So the set is {2, 3, ..., floor(r) if r not integer, or up to r-1 if integer}. For this set to contain exactly two integers, we need exactly two numbers m with 2 ≤ m < r. Since the smallest is 2, we need that r ∈ (3,4]? Let's find: If r ∈ (2,3], then m=2 only (if r>2, then m=2 is < r, and if r ≤3, then m=3? Actually if r ∈ (2,3], then m=2 satisfies m < r? For r=2.5, m=2 < 2.5, so m=2 included; m=3? 3 < 2.5 false. So only m=2. So that's one integer. If r ∈ (3,4], then m=2 and 3 are < r? For r=3.5, m=2,3 are <3.5, so two integers. If r=4 exactly, then m<4 gives m=2,3 → two integers. If r ∈ (4,5), then m=2,3,4 → three integers. So for exactly two integers, we need r ∈ (3,4] (i.e., 3 < r ≤ 4) or possibly r ∈ (3,4)? But if r is just above 3, say 3.1, then m=2,3 are <3.1, so two integers. If r=3 exactly, then m<3 gives m=2 only (since m integer, m=2 <3, m=3 is not <3). So r=3 gives only one integer. So r must be >3? Actually r must be >3? Wait check: For r=3.0, m<3 gives m=2 only (since m integer, m≤2). So only one. So to have two integers (2 and 3), we need r > 3? Because then both 2 and 3 are less than r. But if r=3.1, then 3 < 3.1, so 3 is included. So r > 3. Also need r ≤ BJP? To avoid including 4, we need r ≤ 4? Because if r > 4, then 4 < r, so 4 is included, giving three integers. So r ∈ (3,4] yields exactly two integers (2 and 3). But if r=4, then m<4 gives m=2,3 → two integers. So r ∈ (3,4] works. However, we must also consider if r is exactly 3? No, that gives one integer. So the condition is r ∈ (3,4].

Thus for t=2, if r > 2, the scenario for exactly two natural numbers m with L(m)<0 is r ∈ (3,4].

Now check if r can be in (3,4] given other constraints: r > 1, so fine.

Now we also have that the two m values are 2 and 3 (since t=2, so m starts at 2). So the set is {2,3}. Therefore, we must have {g(-1), -7/2 g(1)} = {2,3}.

Thus g(-1) and -7/2 g(1) are 2 and 3 in some order.

Now we have expressions:

g(1) = A(1 - r) = -A(r - 1). Since r > 3, r-1 > 2, so g(1) is negative (since -A(positive) negative). Good.

g(-1) = 3A(1 + r) (since t=2 > -1). So g(-1) = 3A(r+1).

Now -7/2 g(1) = -7/2 * A(1 - r) = -7/2 * A(1 - r) = -7A(1 - r)/2 = 7A(r - 1)/2.

Because -(1 - r) = r-1. So -7/2 g(1) = (7A/2)(r - 1).

Thus we have two positive numbers: X = g(-1) = 3A(r+1) and Y = -7/2 g(1) = (7A/2)(r-1). And {X, Y} = {2, 3}.

So we have two possibilities:

Possibility 1: X = 2, Y = 3. Possibility 2: X = 3, Y = 2.

Let's write equations.

Given r ∈ (3,4] and A > 0.

Equation X = 3A(r+1) = either 2 or 3. Y = (7A/2)(r-1) = the other.

Since r+1 > 4, actually r>3 => r+1 > 4, so 3A(r+1) > 12A. For this to be as small as 2 or 3, A must be very small, like <0.5. But then Y = (7A/2)(r-1) would be even smaller? Let's compute approximate: if r≈3.5, r+1=4.5, X=3A4.5=13.5A. To be 2 or 3, A≈0.15-0.2. Then Y = (7A/2)(2.5)= (7A1.25?) Actually (r-1)=2.5, so Y = (7A/2)2.5 = 7A1.25 = 8.75A. With A≈0.15, Y≈1.3125. Not 3 or 2. So unlikely to get integers 2 and 3. But maybe with exact values we could solve. Let's solve exactly.

Set X = 3A(r+1) = 2, Y = (7A/2)(r-1) = 3 => from X, A = 2/(3(r+1)). Plug into Y: (7/2)(2/(3(r+1)))(r-1) = (7/2)(2/3)( (r-1)/(r+1) ) = (7/3)*((r-1)/(r+1))? Let's compute carefully:

Y = (7A/2)(r-1) = (7/2)(r-1) * A. With A = 2/(3(r+1)). So Y = (7/2)(r-1) * (2/(3(r+1))) = (7)(r-1) / (3(r+1)). Because (7/2)*2 = 7, denominator 3(r+1). So Y = 7(r-1) / (3(r+1)). Set Y = 3 => 7(r-1) = 9(r+1) => 7r - 7 = 9r + 9 => -7 -9 = 9r - 7r? Actually 7r - 7 = an 9r + 9 => bring terms: 7r - 7 - 9r - 9 = 0 => -2r -16 = 0 => r = -8. Not in (3,4]. So impossible.

Other possibility: X = 3, Y = 2. Then 3A(r+1) = 3 => A = 1/(r+1). Then Y = (7/2)(r-1) * A = (7/2)(r-1)/(r+1) = 2 => (7(r-1))/(2(r+1)) = 2 => 7(r-1) = 4(r+1) => 7r - 7 = 4r + 4 => 3r = 11 => r = 11/3 ≈ 3. FG. Then A = 1/(r+1) = 1/(14/3) = 3/14. So A = 3/14, r = 11/3. Check r ∈ (3,4]? 11/3 ≈ 3.666..., which is indeed in (3,4]. Good. Then compute X = g(-1) = 3A(r+1) = 3*(3/14)(11/3+1) = (9/14)((11+3)/3?) Wait r+1 = 11/3 + 1 = 14/3. So X = 3 * (3/14) * (14/3) = 3 * (3/14)(14/3) = 3 * 1 = 3. Because (3/14)(14/3)=1. So X = 3. And Y = -7/2 g(1) = (7A/2)(r-1) = (7*(3/14)/2)(r-1) = (3/4)(r-1)? Actually compute: A=3/14, so (7A/2) = (7*(3/14))/2 = (21/14)/2? Let's do stepwise: 7A/2 = 7*(3/14)/2 = (21/14)/2? Wait 7*(3/)=21/14? Actually 7 * (3/14) = 21/15? No: 7*(3/14) = 21/14? That's 1.5? I'm messing. Let's compute: 7*(3/14) = 21/14? That's 1.5? Actually 73=21, /14 = 1.5 = 3/2. So 7A = 21/15? Let's do fraction: A = 3/14. Then 7A = 7(3/14) = 21/14? 73=21, /14 = 21/14 = 3/2? Actually 21/14 simplifies to 3/2. So 7A = 3/2. Then (7A)/2 = (3/2)/2 = 3/4. So (7A/2) = 3/4. Then Y = (7A/2)(r-1) = (3/4)(r-1). r-1 = 11/3 - 1 = 8/3. So Y = (3/4)*(8/3) = 8/4 = 2. So Y = 2. Good. So indeed with X=3, Y=2, we get r = 11/3, A = 3/14. And we have X=3, Y=2. So {g(-1), -7/2 g(1)} = {3,2} which is {2,3}. And g(-1)=3, -7/2 g(1)=2. Then g(-1) ≠ -7/2 g(1) indeed 3≠2. So condition satisfied.

Now check the other subcase r < t (i.e., r<2) we already saw impossible. So the only viable for t=2 is r ∈ (3,4] and the specific solution we found r=11/3, A=3/14. But we need to ensure that the set of m with L(m)<0 is indeed {2,3} and that these are the only m. We have t=2, r=11/3 ≈ 3.666, so r > t, and r ∈ (3,4] so indeed m=2,3 are the ones. Good.

Now we must also verify condition (A) fully? We already used it to deduce f(0)=0, f(2)=0, which we did. The limit existence for all x is already satisfied because we derived L(m) formula, but also for a not integer, the limit exists? Condition (A) says: For every real a, the limit as x→a+ of g(x)/(x(x-2)) exists. We need to ensure that this holds for our f and g. Since g(x) = ± f(x) and f(x)/(x(x-2)) = A(x - r) for x≠0,2. So for x away from 0,2, g(x)/(x(x-2)) = ± A (x - r). This is continuous except at points where the branch changes (x = t) and at x=0,2. At x = t, we need to check that the right-hand limit exists. Since the expression from left and right might have different signs? Actually the limit as x→a+ is from the right. If a is not a point of branch change? Wait condition (A) only requires the limit from the right at each a. For a ≠ t, in a right neighborhood of a, the branch is constant (either +f or -f) as long as a is not t. So the limit exists and equals ±A(a - r). At a = t, the right-hand limit as x→t+ uses the branch for x>t, which is g(x)=f(x) (since x>t). So limit = A(t - r). The left-hand limit (not required) could be different, but we only need the right-hand limit, which exists. So condition (A) is satisfied regardless of t. Also at x=0 and x=2, the right-hand limit we already computed exists (finite) because we used the simplified expression. So (A) holds.

Thus the solution with t=2, r=11/3, A=3/14 is consistent with all conditions.

But we also have condition that g is continuous on ℝ. That requires f(t)=0. Since t=2, and f(2)=0, which holds. So continuity fine. because at x=t=2, left-hand limit? Actually g is defined as -f(x) for x<2, and f(x) for x≥2. At x=2, g(2)=f(2)=0. For x<2 near 2, g(x) = -f(x). Since f(2)=0, we have lim_{x→2-} g(x) = -f(2) = 0, so continuous. So good.

Thus we have found a valid solution.

Now we also need to consider the possibility t = r. Could there be a solution with t = r? Let's examine quickly to ensure we haven't missed. But we found one solution that satisfies all conditions. The problem likely expects a unique answer for g(-5). So we should compute g(-5) for this solution.

Given f(x) = A x (x-2)(x - r) with A = 3/14, r = 11/3. Then f(-5) = A * (-5) * (-5-2) * (-5 - r) = A * (-5) * (-7) * ( -5 - r). Compute -5 - r = -(5 + r). r = 11/3, so 5 + r = 5 + 11/3 = (15+11)/3 = 16/3. So -5 - r = -16/3. So f(-5) = (3/14) * (-5) * (-7) * (-16/3). Let's compute stepwise:

(-5) * (-7) = 35. So f(-5) = (3/14) * 35 * (-16/3) = (3/14) * (35) * (-16/3) = (3 cancels) = (1/14) * 35 * (-16) = (35 * -16)/14 = (35/14)* -16 = (5/2)* -16? Since 35/14 = 5/2. So (5/2) * (-16) = -5 * 8 = -40. So f(-5) = -40? Wait compute: (5/2)*(-16) = -40. Yes, f(-5) = -40.

Now g(-5) = ? Since t=2, and -5 < 2, so g(-5) = -f(-5) = -(-40) = 40. Because for x < t, g(x) = -f(x). So g(-5) = -f(-5) = 40.

Thus the answer would be 40.

But we must double-check: Is g(-1) = 3? Let's verify: g(-1) = 3A(r+1) = 3*(3/14)(11/3+1) = (9/14)((11+3)/3?) Actually r+1 = 11/3 + 1 = 14/3. So 3A(r+1) = 3*(3/14)(14/3) = 3(3/14)(14/3) = 3 * (3/14 * 14/ = 3? Actually compute: (3/14)(14/3)=1. So 31 =3. Yes. And g(1) = A(1 - r) = (3/14)(1 - 11/3) = (3/14)((3-11)/3) = (3/14)(-8/3) = -8/14 = -4/7. Wait that's not an even integer! But we earlier argued g(1) must be a negative even integer because -7/g(1) must be integer? Let's check: -7/2 * g(1) = -7/2 * (-4/7?) Actually g(1) = -4/7? Let's compute carefully: g(1) = A(1 - r) = (3/14)(1 - 11/3) = (3/14)((3-11)/3) = (3/14)(-8/3) = -8/14 = -4/7. Yes, g(1) = -4/7. Then -7/2 * g(1) = -7/2 * (-4/7) = ( -7 * -4)/(27) = (28)/(14) = 2. So indeed -7/2 g(1) = 2, which is integer. But g(1) itself is -4/7, which is not an even integer; it's a rational number with denominator 7. However, we earlier deduced that g(1) must be an even integer because -7/2 g(1) integer? Let's revisit: We have -7/2 * g(1) must be an integer (specifically a natural number). Let that integer be N. Then g(1) = - (2/7) N. For g(1) to be an integer, N must be divisible by 7. But g(1) does not need to be integer a priori; it's just a value. The condition only requires that -7/2 g(1) is a natural number. That integer could be a multiple of 7, but g(1) itself need not be integer. In our case, N = 2, so g(1) = -2/7 *? Actually if -7/2 g(1) = 2, then g(1) = -4/7, which is not an integer. That's fine. The earlier deduction that g(1) must be even integer was based on the assumption that -7/2 g(1) is integer and that g(1) is integer? But we only know that -7/2 g(1) is integer, not that g(1) is integer. So g(1) can be rational. So my earlier "must be even integer" was too strong; I only need -7/2 g(1) integer. That means g(1) must be a rational number such that (7/2)(-g(1)) is integer. So g(1) = (2/7) * integer? Actually -7/2 g(1) = N ∈ ℕ => g(1) = - (2N)/7. So g(1) is of the form -2N/7. So it can be non-integer. So that's fine.

Thus our solution stands: r = 11/3, A = 3/14, t=2.

Now verify condition (B) thoroughly: The set of natural numbers m for which L(m) < 0 is {g(-1), -7/ agente We are told the set is {g(-1), -7/2 g(1)}. We found g(-1)=3, -7/2 g(1)=2, and indeed the set of m with L(m)<0 is {2,3} (since we computed r=11/3, t=2, so m=2,3). So it matches.

Thus g(-5)=40.

But we should also check if any other case (t=r) could yield a solution, and also ensure that the answer is the same? Probably not; the problem expects a unique answer. So answer likely 40.

But before finalizing, we must ensure that the solution satisfies all conditions, especially condition (A) for every real a. We argued it does. Also need to check that the limit in (A) exists for every a. For a not equal to 0,2,t, the expression is continuous in a neighborhood, so limit exists. At a = 0,2, t, we need to check right-hand limits. At a=0, we need lim_{x→0+} g(x)/(x(x-2)). Since for x>0 small, if t ≤ 0? t=2, so for x>0 small (<2), we are in x < t? Actually t=2, so for x in (0,2), we have x < t, so g(x) = -f(x). So limit = lim_{x→0+} -f(x)/(x(x-2)). Since f(x) = A x (x-2)(x-r), then -f(x)/(x(x-2)) = -A x (x-2)(x-r) / (x(x-2)) = -A (x-r) for x≠0,2. So as x→0+, this tends to -A(0 - r) = A r. With A=3/14, r=1PEG. Then limit = 3/14 * 11/3 = 11/14? Actually A r = (3/14)*(11/3)=11/14. So finite. So exists.

At a=2, we need lim_{x→2+} g(x)/(x(x-2)). For x>2, x > t? t=2, so for x>2, g(x)=f(x). So limit = lim_{x→2+} f(x)/(x(x-2)) = A(2 - r) = (3/14)(2 - 11/3) = (3/14)((6-11)/3) = (3/14)*(-5/3) = -5/14. Finite. So exists.

At a=t=2, we already considered. So (A) holds.

Thus solution valid.

Now compute g(-5) = -f(-5) because -5 < t. f(-5) we computed as -40, so g(-5)=40.

But we must double-check f(-5) calculation carefully.

f(x) = A x (x-2)(x - r). A=3/14, r=11/3.

Compute f(-5): x = -5 x = -5 x-2 = -7 x - r = -5 - 11/3 = -(15/3 + 11/3) = -26/3.

So product = (-5) * (-7) * (-26/3) = (35) * (-26/3) = - (3526)/3 = - (910)/3? Wait 3526 = 910, yes. So product = -910/3.

Then times A = (3/14) * (-910/3) = (3/14)*(-910/3) = -910/14 = -455/7? Let's compute: 910/14 simplifies: divide by 2: 455/7. So -910/14 = -455/7. But earlier I got -40. Something is off.

Let's recompute more carefully.

f(-5) = A * (-5) * (-5-2) * (-5 - r) We have: x = -5 x-2 = -7 x - r = -5 - r = -(5 + r)

So product = (-5) * (-7) * (-(5 + r)) = (-5)*(-7) = 35, then 35 * (-(5+r)) = -35 (5+r).

So f(-5) = A * [ -35 (5 + r) ] = -35 A (5 + r).

Now A = 3/14, r = 11/3. 5 + r = 5 + 11/3 = (15/3 + 11/3) = 26/3. So 5+r = 26/3. Thus f(-5) = -35 * (3/14) * (26/3) = -35 * (3/14) * (26/3) = -35 * (26)/(14) because 3 cancels? Let's do: (3/14)(26/3) = (326)/(143) = 26/14 = 13/7. So f(-5) = -35 * (13/7) = - (35/7)13 = - (5)13 = -65. Because 35/7=5. So f(-5) = -65. Wait earlier I had -40. So there's discrepancy. Let's recalc: Actually (3/14)(26/3) = 26/14 = 13/7. Yes. So -35 * (13/7) = - (3513)/7 = - (455)/? 35/7 = 5, so -513 = -65. So f(-5) = -65. Then g(-5) = -f(-5) = 65. But earlier I got 40. Which is correct? Let's re-evaluate: f(-5) = A * (-5) * (-7) * (-5 - r). That's A * (-5) * (-7) = 35A? Actually (-5)*(-7)=35, correct. Then times (-5 - r) = -(5+r). So total = 35A * (-(5+r)) = -35A(5+r). Yes.

Now A=3/14, 5+r = 5 + 11/3 = (15+11)/3 = 16/3? Wait 5 = 15/3, plus 11/3 = 26/3. So 5+r = 26/3. So -35 * (3/14) * (26/3) = -35 * (26/14) because (3/14)(3? Actually A=3/14, so -35 * (3/14) * (26/3) = -35 * (26/14) because 3 cancels. So -35 * (26/14) = -35 * (13/7) = -(3513)/7 = -455/ ? 35/7=5, so -5*13 = -65. Yes, f(-5) = -65. So g(-5) = -f(-5) = 65.

But earlier I mistakenly used r=11/3 and thought 5+r = 16/3? That was wrong. 5 + 11/3 = 15/3 + 11/3 = 26/3, correct. So f(-5) = -65. So g(-5) = 65.

But earlier I computed -40 using r=11/3 but maybe miscalculated? Let's double-check my earlier alternate calculation: I had f(-5) = (3/14) * (-5) * (-7) * (-26/3) = (3/14) * (-5) * (-7) * (-26/3). Multiply (-5)(-7)=35. So (3/14)35(-26/3) = (3/14)( -26/3? Wait 35 * (-26/3) = (35/3)*(-26) = (35 * -26)/3 = -910/3. Then (3/14) * (-910/3) = -910/14 = -455/7 ≈ -64.2857. Yes -455? Actually -910/14 = -65? Because 910/14 = 65. So -65. So consistent: -65.

Thus g(-5) = 65.

But wait, is g(-5) defined as -f(-5) because -5 < t? t=2, yes. So g(-5) = -f(-5) = 65.

Thus answer should be 65.

But earlier I computed g(-1) = 3 and -7/2 g(1) = 2, giving g(-1)=3. That's consistent with A=3/14, r=11/3. So all good.

Thus final answer is 65.

But before finalizing, we should consider if any other case (t = r) could also yield a valid solution, perhaps giving a different g(-5). But the problem states "Assuming that g(-1) ≠ -7/2 g(1), compute g(-5)." So there might be a unique solution. Our found solution gives g(-5)=65. We should verify no other possibilities.

Let's quickly test t = r case.

Case: t = r, with r ≠ 0,2 (could be other). Then g(-1) depends on whether r > -1 or r < -1. Also g(1) depends on whether r ≤ 1 or r > .

We need the set of m with L(m)<0 to be {g(-1), -7/2 g(1)}. Since t = r, the threshold for s_m is at m = t = r. But note r may not be integer. The condition for L(m)<0 is: if r < m? Actually we derived: L(m)<0 iff (m < t and m > r) or (m ≥ t and m < r). But since t = r, the first case m < r and m > r impossible; second case m ≥ r and m < r also impossible. So no m satisfies L(m)<obian? Wait careful: For t = r, the condition from earlier: s_m = -1 if m < t, +1 if m ≥ t. And L(m)<0 iff s_m (m - r) < 0. So for m < t = r, s_m = -1, condition: -(m - r) < 0 => m - r > 0 => m > r. But m < r and m > r cannot happen. For m ≥ r, s_m = +1, condition: m - r < 0 => m < r, impossible. So indeed no m gives L(m)<0. So the set would be empty. But condition (B) says there are two natural numbers, so t cannot equal r (unless maybe the set is empty, but it's not). So t ≠ r.

Thus t=2, r=11/3 is the only viable from earlier analysis? But we also had t=0 impossible. Could there be t=2 with other r values? We solved the system: {3A(r+1), (7A/2)(r-C (r-1)} = {2,3}. We found one solution: A=3/14, r=11/3 giving {3,2}. Are there other solutions? Let's check if there is also possibility X=2, Y=3 giving r = -8, not in range. So only r=11/3 works. But is it necessary that r ∈ (3,4]? We derived that for t=2 and r > 2, to have exactly two integers m with L(m)<0, we need r ∈ (3,4]. In our solution r=11/3 ≈ 3.666, which is in (3,4). So that's fine. Could there be a scenario where the two m are not 2 and 3 but some other consecutive integers? For t=2, the m's would be 2 and 3 only if the interval [2, r) contains exactly two integers, which forces r ∈ (3,4] as argued. So m=2 and 3 are forced. So indeed the set must be {2,3}. So g(-1) and -7/2 g(1) must be 2 and 3. So we solved that and got unique r and A. So unique.

Could t be something else? t could be r, but we argued that gives empty set for L(m)<0, so not possible. t could be something else? t must be one of 0,2,r. So only possibilities are 0,2,r. So t=2 is the only viable that yields two natural numbers. So solution is unique.

Thus g(-5)=65.

But wait: Did we consider the possibility that t=2 but the two m's could be something else if r is exactly such that [2, r) contains exactly two integers but the integers are not 2 and 3? For example, if r is between 2 and 3, then only m=2 is included (one integer). So not two. If r between 3 and 4, includes 2 and 3. If r between 4 and 5, includes 2,3,4 (three integers). So only r ∈ (3,4] gives exactly two integers (2 and 3). So yes.

Thus answer 65.

Now double-check condition (B) statement: "The set of natural numbers m for which lim_{x→m+} g(x)/(x(x-2)) is negative is set {g(-1), -7/2 g(1)}." It says: "The set of natural numbers m ... is negative is set {g(-1), -\frac{7}{2}g(1)}." So indeed the set containing those two numbers. So that matches our solution.

Thus final answer: 65.

Now we must present the answer in \boxed{65}. But before finalizing, let's ensure there are no mistakes in algebra for g(-5). Let's recompute f(-5) using the factored form:

f(x) = A x (x-2)(x - r). With A=3/14, r=11/3.

Compute f(-5): x = -5 x-2 = -7 x - r = -5 - 11/3 = -(15/3 + 11/3) = -26/3. So product = (-5)(-7) = 35; 35 * (-26/3) = - (3526)/3 = -910/3. Then times A: (3/14) * (-910/3) = -910/14 = -65. Yes.

So g(-5) = -f(-5) = 65.

Thus answer is 65.

Now we should also confirm that g(-1) = 3, -7/2 g(1) = 2, and indeed they are natural numbers. g(-1) = 3, -7/2 g(1) = 2, so the set is {2,3}. Good.

Now we need to output the answer.

Thus final answer: \boxed{65}.

But the problem statement: "Assuming that g(-1) ≠ -7/2 g(1), compute g(-5)." It gave g(-1) and -7/2 g(1) as a set. So our solution satisfies that.

Thus final answer is 65.

Now produce the final response with reasoning and answer.

We need to output with [THOUG] etc? The instruction: "Please reason step by step, and put your final answer within \boxed{}. Use the Python tool for calculations and verification; default to using it unless the answer is immediate. If you use Python, respond with [THOUG] then [PYTHON] code only and stop; provide the final answer after the tool output."

But we are not required to use Python; we can use reasoning. However, they said "Use the Python tool for calculations and verification; default to using it unless the answer is immediate." Possibly they expect we include Python code. But we can just present the reasoning and answer. But the instruction for final answer: "Please reason step by step, and put your final answer within \boxed{}." So we can present the reasoning and then the answer.

But the meta-instruction: "If you use Python, respond with [THOUG] then [PYTHON] code only and stop; provide the final answer after the tool output." That seems like a directive for when we use the Python tool. But we can also not use it. However, to be safe, we could include a small Python verification snippet. But the problem says "Solve the problem efficiently and clearly." I think we can just give the answer.

Given the complexity, I'll provide a clear step-by-step solution and then the answer. But the system message says: "Please reason step by step, and put your final answer within \boxed{}." So I'll output the reasoning and then the answer.

Thus final answer: \boxed{65}. </think>

We are given a cubic polynomial f(x)f(x) with positive leading coefficient and define

[ g(x)=\begin{cases} -f(x), & x<t,\ f(x), & x\ge t, \end{cases} ]

with gg continuous on R\mathbb{R}. This forces f(t)=0f(t)=0. Write f(x)=Ax(x2)(xr)f(x)=A x(x-2)(x-r) with A>0A>0; then t{0,2,r}t\in\{0,2,r\}.

Condition (A) implies that for every real aa, the right‑hand limit [ \lim_{x\to a^+}\frac{g(x)}{x(x-2)} ] exists finitely. As x0,2x\neq0,2, we have [ \frac{f(x)}{x(x-2)}=A(x-r), ] so that [ \frac{g(x)}{x(x-2)}= s_x,A(x-r), ] where sx=+1s_x=+1 if xtx\ge t and sx=1s_x=-1 if x<tx<t. Consequently, for a natural number mm,

[ L(m):=\lim_{x\to m^+}\frac{g(x)}{x(x-2)}= s_m,A(m-r),\qquad s_m=\begin{cases} -1,& m<t,\ +1,& m\ge t. \end{cases} ]

Thus L(m)<0L(m)<0 precisely when [ s_m,(m-r)<0. ]

The analysis of L(m)<0L(m)<0 shows that the set of natural numbers mm with L(m)<0L(m)<0 is

  • {mN:r<m<t}\{m\in\mathbb{N}: r<m<t\} if r<tr<t,
  • {mN:tm<r}\{m\in\mathbb{N}: t\le m<r\} if r>tr>t,
  • empty if r=tr=t.

Since this set must contain exactly two elements (condition (B)), and it must be a set of two consecutive integers, there are two possibilities.

Condition (B) states that this set equals {g(1),  72g(1)}\{\,g(-1),\;-\tfrac72g(1)\,\}, with the two numbers distinct.

We compute g(1)g(1) and g(1)g(-1) in each possible case for tt.

  • If t=0t=0, then g(1)=A(r1)g(1)=A(r-1), g(1)=3A(1+r)g(-1)=3A(1+r). Then the analysis shows it is impossible to obtain exactly two natural numbers mm with L(m)<0L(m)<0 while also having g(1)<0g(1)<0 (needed for 72g(1)>0-\tfrac72g(1)>0). Hence t0t\neq0.

  • If t=2t=2, then g(1)=A(1r)g(1)=A(1-r), g(1)=3A(1+r)g(-1)=3A(1+r). For g(1)<0g(1)<0 we need r>1r>1. The condition L(m)<0L(m)<0 for r>t=2r>t=2 gives m=2,3m=2,3 exactly when r(3,4]r\in(3,4]. Thus the two natural numbers are 22 and 33, so we must have [ {g(-1),;-\tfrac72g(1)}={2,3}. ]

Now g(1)=A(1r)g(1)=A(1-r) and 72g(1)=72A(r1)-\tfrac72g(1)=\tfrac72A(r-1). Substituting r>3r>3, we solve the system

[ \begin{cases} 3A(r+1)=2,\quad \tfrac{7}{2}A(r-1)=3 & \text{or} \ 3A(r+1)=3,\quad \tfrac{7}{2}A(r-1)=2. \end{cases} ]

The first system leads to r=8r=-8, which contradicts r>3r>3. The second gives [ 3A(r+1)=3,\qquad \tfrac{7}{2}A(r-1)=2. ] From the first, A=1r+1A=\frac{1}{r+1}. Plug into the second: [ \tfrac{7}{2}\cdot\frac{r-1}{r+1}=2 \quad\Longrightarrow\quad 7(r-1)=4(r+1) \quad\Longrightarrow\quad 3r=11 \quad\Longrightarrow\quad r=\frac{11}{3}. ] Then A=1r+1=1143=314A=\frac{1}{r+1}=\frac{1}{\frac{14}{3}}=\frac{3}{14}. Indeed r=113(3,4]r=\frac{11}{3}\in(3,4], and we obtain [ g(-1)=3A(r+1)=3\cdot\frac{3}{14}\cdot\frac{14}{3}=3,\qquad -\tfrac72g(1)=\tfrac{7}{2}A(r-1)=\tfrac{7}{2}\cdot\frac{3}{14}\cdot\tfrac{8}{3}=2. ] Thus {g(1),72g(1)}={3,2}\{g(-1),\,-\tfrac72g(1)\}=\{3,2\}, matching the required set {2,3{\{2,3\{. Moreover g(1)72g(1)g(-1)\neq -\tfrac72g(1) holds.

Hence t=2t=2, r=113r=\frac{11}{3}, A=314A=\frac{3}{14}.

Finally, g(5)=f(5)g(-5)=-f(-5) because 5<t=2-5<t=2. Compute [ f(-5)=A(-5)(-7)\bigl(-5-\tfrac{11}{3}\bigr)=\frac{3}{14}\cdot35\cdot\bigl(-\tfrac{26}{3}\bigr)= -\frac{35\cdot26}{14}= -65, ] so g(5)=(65)=65g(-5)=-(-65)=65.

[ \boxed{65} ]

Tool Output
[PYTHON OUTPUT] SyntaxError: unterminated string literal (detected at line 1) (<string>, line 1) [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] We need to verify g(-5) using the derived parameters: A=3/14, r=11/3, t=2. Compute f(x) = Ax(x-2)*(x - r). Then g(x) = -f(x) for x < t, and = f(x) for x >= t. Then compute g(-5). Use Python to confirm the value is 65. [/THOUGHT] [PYTHON] import sympy as sp

Define parameters

A = sp.Rational(3, 14) # 3/14 r = sp.Rational(11, 3) # 11/3 t = 2

Define f(x)

x = sp.symbols('x') f = A * x * (x - 2) * (x - r)

Define g(x)

g = sp.Piecewise((-f, x < t), (f, True))

Compute g(-5)

g_minus_5 = g.subs(x, -5) print(g_minus_5) print(float(g_minus_5)) [/PYTHON]

Tool Output
[PYTHON OUTPUT] 65 65.0 [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] The Python computation shows g(-5) = 65.

\boxed{65}

Final Model Output
65

Comparative Analysis (P33) (Average across runs)

Avg Time Taken

Deepseek-V3.2
1184.1
K-EXAONE-236B-A23B
994.5
GPT-5.1 (high)
503.1
Solar-Open-100B
488.8
Solar-Pro-2 (31B)(high)
422.0
Grok-4.1-fast
366.9
K-EXAONE-236B-A23B
268.6
Kanana-2-30B-Thinking
188.6
Gemini-3-Pro-Preview
183.0
Kanana-2-30B-Thinking-2601
170.5
GPT-5.2 (high)
154.8
EXAONE-4.0.1-32B (high)
152.2
Llama-VARCO-8B-Instruct
151.6
Claude-Opus-4.5
47.4
A.X-4.0 (72B)
27.8
HCX-007(high)
22.6
axk1
11.7

Avg Token Usage

K-EXAONE-236B-A23B
100286.0
Solar-Open-100B
70810.0
K-EXAONE-236B-A23B
58118.0
Grok-4.1-fast
57340.0
Kanana-2-30B-Thinking-2601
34034.0
Kanana-2-30B-Thinking
29518.0
GPT-5.1 (high)
29140.0
Deepseek-V3.2
25475.0
Solar-Pro-2 (31B)(high)
20065.0
Gemini-3-Pro-Preview
17873.0
GPT-5.2 (high)
12962.0
Llama-VARCO-8B-Instruct
9839.0
Claude-Opus-4.5
8374.0
EXAONE-4.0.1-32B (high)
5810.0
axk1
3667.0
A.X-4.0 (72B)
2546.0
HCX-007(high)
2466.0