Problem Analysis #7

Claude Opus 4.8 · Run 1

Correct
3.62s
570 toks

API · no tools. This is the prompt and response recorded for this attempt; a full solution may not have been returned.

Problem Statement

Return a single integer only. The problem has been revised so that no final answer is an irrational number, a parameterized expression, a range, a proof, a drawing, a graph, a locus equation, or a region description.

Let f(x)=2x34x2+3f(x)=2x^3-4x^2+3. For 0<t<40<t<4, let CtC_t be the circle passing through (t,f(t))(t,f(t)), having the same tangent there as y=f(x)y=f(x), and having its center on the xx-axis. If the center is (c(t),0)(c(t),0) and the radius is r(t)r(t), find

c(1)+r(1)2.c(1)+r(1)^2.
Ground Truth
4
Recorded model response / solution
Reasoning Process

f(x)=2x³-4x²+3, f'(x)=6x²-8x.

At t=1: f(1)=2-4+3=1, f'(1)=6-8=-2.

The circle has center (c,0) on x-axis. The radius to the point (1,1) must be perpendicular to the tangent line (slope -2). So the normal line at (1,1) has slope 1/2.

Center lies along the normal line from the point. Normal direction slope = 1/2. Line: y - 1 = (1/2)(x - 1). Set y=0: -1 = (1/2)(x-1), x-1 = -2, x = -1.

So c = -1.

r² = (1-(-1))² + (1-0)² = 4 + 1 = 5.

c + r² = -1 + 5 = 4.

\boxed{4}

Final Model Output
4

Comparative Analysis (P7) (Average across runs)

Averages use reported measurements only. Missing usage is not treated as zero.

Avg Time Taken

DeepSeek V4 Pro
20.2
K-EXAONE-236B-A23B
19.9
Gemini 3.5 Flash
9.1
GPT-5.5
7.4
Solar Pro 3
6.1
Claude Opus 4.8
3.7
KT Mi:dm 2.0 Base Instruct
3.3

Avg Token Usage

K-EXAONE-236B-A23B
2869.7
Gemini 3.5 Flash
2161.0
KT Mi:dm 2.0 Base Instruct
1865.7
Solar Pro 3
1143.3
DeepSeek V4 Pro
995.7
Claude Opus 4.8
551.0
GPT-5.5
523.3
    Tokyo · Problem 7 · Claude Opus 4.8 | EntropyMath