Problem Analysis #4

A.X-4.0 (72B) · Run 1

17.89s
3,749 toks
Problem Statement

Suppose the following limit is given:

limn[0,n](1+20569nx)69ne(67x)dx=pq,\lim_{n\to\infty} \int_{[0,n]} \left(1+\frac{205}{69n}x\right)^{-69n} e^{(-\frac{6}{7}x)}\,dx=\frac{p}{q},

where pp and qq are positive integers which are relatively prime. Find p2qp^2q.

\noindent

Ground Truth
70609
Execution Trace
Reasoning Process

[THOUGHT] To solve this problem, I'll first simplify the integrand inside the limit. Note that as nn \to \infty, the expression (1+20569nx)69n\left(1+\frac{205}{69n}x\right)^{-69n} converges to the exponential function. Specifically, we recognize the standard limit:

limn(1+anx)n=eax.\lim_{n \to \infty} \left(1 + \frac{a}{n}x\right)^{-n} = e^{-ax}.

In our problem, a=20569a = \frac{205}{69}, so:

(1+20569nx)69ne20569x.\left(1+\frac{205}{69n}x\right)^{-69n} \to e^{-\frac{205}{69}x}.

Therefore, the limit of the integrand becomes:

e20569xe67x=e(20569+67)x.e^{-\frac{205}{69}x} \cdot e^{-\frac{6}{7}x} = e^{-\left(\frac{205}{69} + \frac{6}{7}\right)x}.

Next, we need to compute the sum:

20569+67.\frac{205}{69} + \frac{6}{7}.

To add these fractions, find a common denominator, which is 483483 (since 69×7=48369 \times 7 = 483):

20569=205×7483=1435483,\frac{205}{69} = \frac{205 \times 7}{483} = \frac{1435}{483}, 67=6×69483=414483.\frac{6}{7} = \frac{6 \times 69}{483} = \frac{414}{483}.

Now add the fractions:

1435483+414483=1849483.\frac{1435}{483} + \frac{414}{483} = \frac{1849}{483}.

The integral then becomes:

limn0ne1849483xdx.\lim_{n\to\infty} \int_0^n e^{-\frac{1849}{483}x} \, dx.

As nn \to \infty, this integral evaluates to the improper integral:

0e1849483xdx.\int_0^\infty e^{-\frac{1849}{483}x} \, dx.

This is a standard exponential integral which evaluates to:

0ekxdx=1k,\int_0^\infty e^{-kx} \, dx = \frac{1}{k},

where k=1849483k = \frac{1849}{483}. Thus, the integral is:

11849483=4831849.\frac{1}{\frac{1849}{483}} = \frac{483}{1849}.

We simplify this fraction by finding the greatest common divisor (GCD) of 483483 and 18491849. Using the Euclidean algorithm:

1849=483×3+420,1849 = 483 \times 3 + 420, 483=420×1+63,483 = 420 \times 1 + 63, 420=63×6+42,420 = 63 \times 6 + 42, 63=42×1+21,63 = 42 \times 1 + 21, 42=21×2+0.42 = 21 \times 2 + 0.

So, gcd(483,1849)=21\gcd(483, 1849) = 21. Simplifying:

48321=23,184921=89.\frac{483}{21} = 23, \quad \frac{1849}{21} = 89.

Thus, the fraction simplifies to 2389\frac{23}{89}, where 23 and 89 are coprime.

Finally, we need to find p2qp^2q where pq=2389\frac{p}{q} = \frac{23}{89}:

p=23,q=89.p = 23, \quad q = 89.

So:

p2q=232×89=529×89.p^2q = 23^2 \times 89 = 529 \times 89.

I will now calculate 529×89529 \times 89 using Python. [/THOUGHT] [PYTHON] p = 23 q = 89 result = p**2 * q print(result)

Tool Output
[PYTHON OUTPUT] 47081 None [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] The calculation of 529×89529 \times 89 using Python yielded the result 47081. Therefore, the value of p2qp^2q is:

47081\boxed{47081}
Final Model Output
47081

Comparative Analysis (P4) (Average across runs)

Avg Time Taken

Solar-Open-100B
438.0
Deepseek-R1-distill-Qwen-32B (high)
140.9
Deepseek-V3.2
123.2
Gemini-3-Pro-Preview
90.8
Kanana-2-30B-Thinking
87.7
GPT-oss-20B (high)
60.4
Solar-Pro-2 (31B)(high)
60.2
K-EXAONE-236B-A23B
53.2
Grok-4.1-fast
38.4
HCX-007(high)
31.5
Gemma-3-27B
31.4
Qwen3-30B-A3B-2507
28.9
Kanana-2-30B-Thinking-2601
22.7
Llama-VARCO-8B-Instruct
21.3
GPT-5.1 (high)
19.0
Claude-Opus-4.5
16.4
A.X-4.0 (72B)
16.0
EXAONE-4.0.1-32B (high)
3.7

Avg Token Usage

K-EXAONE-236B-A23B
20,406
Kanana-2-30B-Thinking
13,425
Gemini-3-Pro-Preview
11,241
Deepseek-V3.2
9,875
Solar-Pro-2 (31B)(high)
9,831
GPT-oss-20B (high)
9,757
Solar-Open-100B
8,096
Grok-4.1-fast
7,672
Kanana-2-30B-Thinking-2601
6,314
Qwen3-30B-A3B-2507
6,267
HCX-007(high)
4,190
Deepseek-R1-distill-Qwen-32B (high)
3,984
Claude-Opus-4.5
3,858
A.X-4.0 (72B)
3,485
EXAONE-4.0.1-32B (high)
3,238
GPT-5.1 (high)
3,068
Llama-VARCO-8B-Instruct
2,088
Gemma-3-27B
1,706