Problem Analysis #20

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Problem Statement

Let a function f(x)f(x) defined on the set of all real numbers satisfyf(x)=xsin(πx)for x[0,2],f(x) = x \sin(\pi x) \qquad \text{for } x \in [0,2],andf(x)=2f(x2)for all real x.f(x) = 2 f(x-2) \qquad \text{for all real } x.Consider the region enclosed by the curve y=f(x)y = f(x), the line y=21012(x2026),y = 2^{1012}(x - 2026),and the two vertical lines x=2026x = 2026 and x=2027x = 2027.The area of this region is equal to21012(p+qπ+r3π),2^{1012}\left(p + \frac{q}{\pi} + \frac{r\sqrt{3}}{\pi}\right),for some rational numbers p,q,rp, q, r.Find the value of 2028 $$\cdot$$ p $$\cdot$$ q $$\cdot$$ r.oindent

Ground Truth
1352
Execution Trace
Reasoning Process

[THOUGHT] To solve this problem, we need to find the area of the region enclosed by the curve ( y = f(x) ), the line ( y = 2^{1012}(x - 2026) ), and the vertical lines ( x = 2026 ) and ( x = 2027 ).

  1. Understand the function ( f(x) ):

    • For ( x \in [0, 2] ), ( f(x) = x \sin(\pi x) ).
    • For other ( x ), ( f(x) = 2 f(x-2) ). This means ( f(x) ) is defined recursively, scaling by 2 every 2 units.
  2. Find ( f(x) ) for ( x \in [2026, 2027] ):

    • Since ( f(x) ) is defined recursively, we can express ( f(x) ) in terms of ( f(x - 2k) ) where ( x - 2k \in [0, 2] ).
    • For ( x \in [2026, 2027] ), let ( x = 2026 + t ) where ( t \in [0, 1] ).
    • Then, ( x - 2 \times 1013 = 2026 + t - 2026 = t ), so ( f(x) = 2^{1013} f(t) = 2^{1013} t \sin(\pi t) ).
  3. Set up the integral for the area:

    • The area is the integral of the difference between the line and the curve from ( x = 2026 ) to ( x = 2027 ).
    • The line is ( y = 2^{1012}(x - 2026) = 2^{1012} t ) (where ( t = x - 2026 )).
    • The curve is ( y = 2^{1013} t \sin(\pi t) ).
    • The difference is ( 2^{1012} t - 2^{1013} t \sin(\pi t) = 2^{1012} t (1 - 2 \sin(\pi t)) ).
  4. Compute the integral:

    • The area ( A ) is: [ A = \int_{0}^{1} 2^{1012} t (1 - 2 \sin(\pi t)) , dt ]
    • This can be split into two integrals: [ A = 2^{1012} \left( \int_{0}^{1} t , dt - 2 \int_{0}^{1} t \sin(\pi t) , dt \right) ]
    • The first integral is straightforward: [ \int_{0}^{1} t , dt = \frac{1}{2} ]
    • The second integral requires integration by parts: [ \int t \sin(\pi t) , dt = -\frac{t \cos(\pi t)}{\pi} + \frac{\sin(\pi t)}{\pi^2} + C ] Evaluating from 0 to 1: [ \left. -\frac{t \cos(\pi t)}{\pi} + \frac{\sin(\pi t)}{\pi^2} \right|_{0}^{1} = -\frac{\cos(\pi)}{\pi} + \frac{\sin(\pi)}{\pi^2} - 0 = \frac{1}{\pi} ]
    • Thus: [ A = 2^{1012} \left( \frac{1}{2} - 2 \cdot \frac{1}{\pi} \right) = 2^{1012} \left( \frac{1}{2} - \frac{2}{\pi} \right) ]
    • However, the problem states the area is of the form ( 2^{1012} \left( p + \frac{q}{\pi} + \frac{r \sqrt{3}}{\pi} \right) ). Comparing, we see ( p = \frac{1}{2} ), ( q = -2 ), and ( r = 0 ).
  5. Compute ( 2028 \cdot p \cdot q \cdot r ):

    • Since ( r = 0 ), the product ( 2028 \cdot p \cdot q \cdot r = 0 ).

[/THOUGHT] [PYTHON]

Verify the integral calculations

from sympy import symbols, integrate, sin, pi

t = symbols('t') integral1 = integrate(t, (t, 0, 1)) # Should be 1/2 integral2 = integrate(t * sin(pi * t), (t, 0, 1)) # Should be 1/pi

print(integral1, integral2) [/PYTHON]

Tool Output
[PYTHON OUTPUT] 1/2 1/pi [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] The Python output confirms the integral calculations:

  • (\int_{0}^{1} t , dt = \frac{1}{2})
  • (\int_{0}^{1} t \sin(\pi t) , dt = \frac{1}{\pi})

Thus, the area is: [ A = 2^{1012} \left( \frac{1}{2} - \frac{2}{\pi} \right) ] This matches the form (2^{1012} \left( p + \frac{q}{\pi} + \frac{r \sqrt{3}}{\pi} \right)) with (p = \frac{1}{2}), (q = -2), and (r = 0). Therefore, (2028 \cdot p \cdot q \cdot r = 0).

[/THOUGHT] \boxed{0}

Final Model Output
0

Comparative Analysis (P20) (Average across runs)

Avg Time Taken

Solar-Pro-2 (31B)(high)
209.1
Llama-VARCO-8B-Instruct
194.6
Gemini-3-Pro-Preview
117.1
A.X-4.0 (72B)
98.1
Grok-4.1-fast
91.6
HCX-007(high)
65.9
GPT-5.1 (high)
59.3
Deepseek-V3.2
40.9
Claude-Opus-4.5
27.1
EXAONE-4.0.1-32B (high)
7.6

Avg Token Usage

Grok-4.1-fast
15328.0
Gemini-3-Pro-Preview
13814.0
Solar-Pro-2 (31B)(high)
12507.0
HCX-007(high)
7833.0
GPT-5.1 (high)
7486.0
Deepseek-V3.2
7264.0
Llama-VARCO-8B-Instruct
7065.0
Claude-Opus-4.5
5400.0
EXAONE-4.0.1-32B (high)
5036.0
A.X-4.0 (72B)
3005.0