Problem Analysis #2

EXAONE-4.0-32B · Run 1

19.75s
4,141 toks
Problem Statement

Let

f(z)=z2,f(z) = z^{2},

and consider the upper semicircular arc

C:z=52eiθ,0θπ.C : z = \frac{5}{2} e^{i\theta}, \qquad 0 \le \theta \le \pi.

Let

L={xR:52x52},L = \{\, x \in \mathbb{R} : -\tfrac{5}{2} \le x \le \tfrac{5}{2} \,\},

and form the closed contour

Γ=CL,\Gamma = C \cup L,

where CC is traversed from z=52z = \tfrac{5}{2} to z=52z = -\tfrac{5}{2}, and LL is traversed from x=52x = -\tfrac{5}{2} to x=52x = \tfrac{5}{2}.\

Suppose the contour integral

Cf(z)dz=pq,\int_C f(z)\, dz=-\frac{p}{q},

where pp and qq are positive integers which are relatively prime. Find p+qp+q.

Ground Truth
137
Execution Trace
Reasoning Process

[THOUGHT] I need to compute the contour integral of f(z)=z2f(z) = z^2 over the upper semicircular arc CC. The contour CC is parameterized by z=52eiθz = \frac{5}{2} e^{i\theta} for 0θπ0 \le \theta \le \pi. To compute the integral, I will parameterize the contour and then evaluate the integral using the parameter θ\theta.

The integral over CC is given by:

Cf(z)dz=0πf(52eiθ)52ieiθdθ.\int_C f(z) \, dz = \int_0^\pi f\left( \frac{5}{2} e^{i\theta} \right) \cdot \frac{5}{2} i e^{i\theta} \, d\theta.

Substituting f(z)=z2f(z) = z^2, we get:

0π(52eiθ)252ieiθdθ=0π254e2iθ52ieiθdθ.\int_0^\pi \left( \frac{5}{2} e^{i\theta} \right)^2 \cdot \frac{5}{2} i e^{i\theta} \, d\theta = \int_0^\pi \frac{25}{4} e^{2i\theta} \cdot \frac{5}{2} i e^{i\theta} \, d\theta.

Simplifying the integrand:

25452ie3iθ=1258ie3iθ.\frac{25}{4} \cdot \frac{5}{2} i \cdot e^{3i\theta} = \frac{125}{8} i e^{3i\theta}.

Now, I will compute this integral using Python to ensure accuracy. [/THOUGHT] [PYTHON] import numpy as np from scipy.integrate import quad

Define the integrand

def integrand(theta): return (125/8) * 1j * np.exp(3j * theta)

Compute the integral over theta from 0 to pi

result, _ = quad(lambda theta: np.real(integrand(theta)), 0, np.pi) + 1j * quad(lambda theta: np.imag(integrand(theta)), 0, np.pi)

The result should be purely imaginary, so we simplify

p = abs(result.imag) q = 1

Since the result is purely imaginary, we can extract the coefficient

The exact value is (125/8) * i * integral of e^{3iθ\theta} from 0 to pi

The integral of e^{3iθ\theta} is (e^{3iπ\pi} - 1)/(3i) = (e^{iπ\pi} - 1)/(3i) = (-1 - 1)/(3i) = -2/(3i) = 2i/3

So the total integral is (125/8) * i * (2i/3) = (125/8) * (-2/3) = -125/12

Thus, the integral is -125/12, so p = 125, q = 12, and p + q = 137

But let's verify numerically

print(result) [/PYTHON]

Tool Output
[PYTHON OUTPUT] TypeError: can't multiply sequence by non-int of type 'complex' [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] The Python code encountered a TypeError because the function did not handle the complex multiplication correctly. Let me re-evaluate the integral analytically to avoid the error. The integral simplifies to:

0π1258ie3iθdθ=1258i[e3iθ3i]0π=1258e3iπ13=12524(e3iπ1).\int_0^\pi \frac{125}{8} i e^{3i\theta} \, d\theta = \frac{125}{8} i \cdot \left[ \frac{e^{3i\theta}}{3i} \right]_0^\pi = \frac{125}{8} \cdot \frac{e^{3i\pi} - 1}{3} = \frac{125}{24} (e^{3i\pi} - 1).

Since e3iπ=1e^{3i\pi} = -1, the result is:

12524(11)=12524(2)=12512.\frac{125}{24} (-1 - 1) = \frac{125}{24} \cdot (-2) = -\frac{125}{12}.

Thus, p=125p = 125 and q=12q = 12, so p+q=137p + q = 137. [/THOUGHT] 137\boxed{137}

Final Model Output
137

Comparative Analysis (P2) (Average across runs)

Avg Time Taken

Gemini-3-Pro-Preview
56.5
HCX-007
42.2
K-EXAONE-236B-A23B
39.8
Kanana-2-30B-Thinking
35.4
GLM-4.5-Air
29.0
Kanana-2-30B-Thinking-2601
28.5
Solar-Open-100B
16.1
Solar-Pro 2
15.4
GPT-5.2 (high)
10.0
EXAONE-4.0-32B
9.0

Avg Token Usage

Gemini-3-Pro-Preview
8640.0
Kanana-2-30B-Thinking-2601
7490.0
Kanana-2-30B-Thinking
7071.0
HCX-007
5399.3
Solar-Pro 2
5336.0
Solar-Open-100B
4666.0
K-EXAONE-236B-A23B
4476.7
GLM-4.5-Air
3903.0
EXAONE-4.0-32B
3641.0
GPT-5.2 (high)
3069.0