Problem Analysis #19

A.X-4.0 (72B) · Run 1

43.25s
6,621 toks
Problem Statement

For all x>0x > 0, let y1(x)y_1(x), y2(x)y_2(x), and y3(x)y_3(x) be the functions satisfying

dy1dx(sinx)2y1=0,y1(1)=5,\frac{dy_1}{dx} - (\sin x)^2 y_1 = 0, \quad y_1(1) = 5, dy2dx(cosx)2y2=0,y2(1)=13,\frac{dy_2}{dx} - (\cos x)^2 y_2 = 0, \quad y_2(1) = 13, dy3dx(2x3x3)y3=0,y3(1)=35e,\frac{dy_3}{dx} - \left(\frac{2 - x^3}{x^3}\right) y_3 = 0, \quad y_3(1) = 35e,

respectively. Find the value of

limx0+y1(x)y2(x)y3(x)+989xx3esinx.\lim_{x \to 0^+} \frac{y_1(x)y_2(x)y_3(x) + 989x}{x^3 e \sin x}.

\

Ground Truth
989
Execution Trace
Reasoning Process

[THOUGHT] First, I need to solve for the functions y1(x)y_1(x), y2(x)y_2(x), and y3(x)y_3(x) using their respective differential equations and initial conditions.

The differential equation for y1(x)y_1(x) is:

dy1dx(sinx)2y1=0\frac{dy_1}{dx} - (\sin x)^2 y_1 = 0

This can be solved using separation of variables:

dy1y1=(sinx)2dx\frac{dy_1}{y_1} = (\sin x)^2 \, dx

Integrating both sides:

lny1=(sinx)2dx\ln |y_1| = \int (\sin x)^2 \, dx

Using the identity (sinx)2=1cos(2x)2(\sin x)^2 = \frac{1 - \cos(2x)}{2}:

lny1=1cos(2x)2dx=12(xsin(2x)2)+C\ln |y_1| = \int \frac{1 - \cos(2x)}{2} \, dx = \frac{1}{2} \left( x - \frac{\sin(2x)}{2} \right) + C

Exponentiating both sides:

y1=ex2sin(2x)4+C=eCex2sin(2x)4y_1 = e^{\frac{x}{2} - \frac{\sin(2x)}{4} + C} = e^C e^{\frac{x}{2} - \frac{\sin(2x)}{4}}

Using the initial condition y1(1)=5y_1(1) = 5:

5=eCe12sin(2)45 = e^C e^{\frac{1}{2} - \frac{\sin(2)}{4}}

Thus:

eC=5e12+sin(2)4e^C = 5 e^{-\frac{1}{2} + \frac{\sin(2)}{4}}

So:

y1(x)=5e12+sin(2)4ex2sin(2x)4=5ex12+sin(2)sin(2x)4y_1(x) = 5 e^{-\frac{1}{2} + \frac{\sin(2)}{4}} e^{\frac{x}{2} - \frac{\sin(2x)}{4}} = 5 e^{\frac{x - 1}{2} + \frac{\sin(2) - \sin(2x)}{4}}

The differential equation for y2(x)y_2(x) is:

dy2dx(cosx)2y2=0\frac{dy_2}{dx} - (\cos x)^2 y_2 = 0

Similarly, using separation of variables:

dy2y2=(cosx)2dx\frac{dy_2}{y_2} = (\cos x)^2 \, dx

Integrating both sides:

lny2=(cosx)2dx\ln |y_2| = \int (\cos x)^2 \, dx

Using the identity (cosx)2=1+cos(2x)2(\cos x)^2 = \frac{1 + \cos(2x)}{2}:

lny2=1+cos(2x)2dx=12(x+sin(2x)2)+C\ln |y_2| = \int \frac{1 + \cos(2x)}{2} \, dx = \frac{1}{2} \left( x + \frac{\sin(2x)}{2} \right) + C

Exponentiating both sides:

y2=ex2+sin(2x)4+C=eCex2+sin(2x)4y_2 = e^{\frac{x}{2} + \frac{\sin(2x)}{4} + C} = e^C e^{\frac{x}{2} + \frac{\sin(2x)}{4}}

Using the initial condition y2(1)=13y_2(1) = 13:

13=eCe12+sin(2)413 = e^C e^{\frac{1}{2} + \frac{\sin(2)}{4}}

Thus:

eC=13e12sin(2)4e^C = 13 e^{-\frac{1}{2} - \frac{\sin(2)}{4}}

So:

y2(x)=13e12sin(2)4ex2+sin(2x)4=13ex12+sin(2x)sin(2)4y_2(x) = 13 e^{-\frac{1}{2} - \frac{\sin(2)}{4}} e^{\frac{x}{2} + \frac{\sin(2x)}{4}} = 13 e^{\frac{x - 1}{2} + \frac{\sin(2x) - \sin(2)}{4}}

The differential equation for y3(x)y_3(x) is:

dy3dx(2x3x3)y3=0\frac{dy_3}{dx} - \left( \frac{2 - x^3}{x^3} \right) y_3 = 0

Using separation of variables:

dy3y3=(2x31x)dx\frac{dy_3}{y_3} = \left( \frac{2}{x^3} - \frac{1}{x} \right) \, dx

Integrating both sides:

lny3=(2x31x)dx=1x2lnx+C\ln |y_3| = \int \left( \frac{2}{x^3} - \frac{1}{x} \right) \, dx = -\frac{1}{x^2} - \ln |x| + C

Exponentiating both sides:

y3=e1x2lnx+C=eCe1x21xy_3 = e^{-\frac{1}{x^2} - \ln x + C} = e^C e^{-\frac{1}{x^2}} \cdot \frac{1}{x}

Using the initial condition y3(1)=35ey_3(1) = 35e:

35e=eCe1135e = e^C e^{-1} \cdot 1

Thus:

eC=35e2e^C = 35e^2

So:

y3(x)=35e2e1x21x=35e2xe1x2y_3(x) = 35e^2 e^{-\frac{1}{x^2}} \cdot \frac{1}{x} = \frac{35e^2}{x} e^{-\frac{1}{x^2}}

Now, we need to find the limit:

limx0+y1(x)y2(x)y3(x)+989xx3esinx\lim_{x \to 0^+} \frac{y_1(x)y_2(x)y_3(x) + 989x}{x^3 e \sin x}

First, compute y1(x)y2(x)y3(x)y_1(x)y_2(x)y_3(x):

y1(x)y2(x)y3(x)=51335e2xex12+sin(2)sin(2x)4ex12+sin(2x)sin(2)4e1x2y_1(x)y_2(x)y_3(x) = 5 \cdot 13 \cdot \frac{35e^2}{x} e^{\frac{x - 1}{2} + \frac{\sin(2) - \sin(2x)}{4}} e^{\frac{x - 1}{2} + \frac{\sin(2x) - \sin(2)}{4}} e^{-\frac{1}{x^2}}

Simplify the exponents:

y1(x)y2(x)y3(x)=2375e21xex11x2y_1(x)y_2(x)y_3(x) = 2375 e^2 \cdot \frac{1}{x} e^{x - 1 - \frac{1}{x^2}}

Thus, the limit becomes:

limx0+2375e21xex11x2+989xx3esinx\lim_{x \to 0^+} \frac{2375 e^2 \cdot \frac{1}{x} e^{x - 1 - \frac{1}{x^2}} + 989x}{x^3 e \sin x} =limx0+2375e2ex11x2+989x2x4esinx= \lim_{x \to 0^+} \frac{2375 e^2 e^{x - 1 - \frac{1}{x^2}} + 989x^2}{x^4 e \sin x}

Using the fact that ex1e1e^{x - 1} \to e^{-1} as x0+x \to 0^+, and e1x20e^{-\frac{1}{x^2}} \to 0 extremely rapidly, the term 2375e2ex11x22375 e^2 e^{x - 1 - \frac{1}{x^2}} becomes negligible compared to 989x2989x^2:

limx0+989x2x4esinx\approx \lim_{x \to 0^+} \frac{989x^2}{x^4 e \sin x} =limx0+989x2esinx= \lim_{x \to 0^+} \frac{989}{x^2 e \sin x}

Using sinxx\sin x \approx x as x0+x \to 0^+:

=limx0+989x3e= \lim_{x \to 0^+} \frac{989}{x^3 e} =989elimx0+1x3= \frac{989}{e} \lim_{x \to 0^+} \frac{1}{x^3}

Since the limit limx0+1x3\lim_{x \to 0^+} \frac{1}{x^3} diverges, the limit of the entire expression also diverges. However, let's verify this through Python for more precision. [/THOUGHT] [PYTHON] import numpy as np

Define the functions y1, y2, and y3

def y1(x): return 5 * np.exp((x - 1)/2 + (np.sin(2) - np.sin(2*x))/4)

def y2(x): return 13 * np.exp((x - 1)/2 + (np.sin(2*x) - np.sin(2))/4)

def y3(x): return (35 * np.exp(2)) / x * np.exp(-1/x**2)

Define the numerator and denominator for the limit

def numerator(x): return y1(x) * y2(x) * y3(x) + 989 * x

def denominator(x): return x**3 * np.exp(1) * np.sin(x)

Calculate the limit as x approaches 0 from the right

x_values = np.linspace(1e-6, 1e-4, 100) limit_values = numerator(x_values) / denominator(x_values)

print(limit_values[-1]) # The last value as x approaches 0

Tool Output
[PYTHON OUTPUT] 363832767924944.3 [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] The Python code evaluates the limit as xx approaches 0+0^+ and provides a numerical result of approximately 363832767924944.3. Since we need to give the final answer as an integer, we round this to the nearest whole number.

The final answer is: 363832767924944\boxed{363832767924944} [/THOUGHT]

Final Model Output
363832767924944

Comparative Analysis (P19) (Average across runs)

Avg Time Taken

Gemini-3-Pro-Preview
894.8
K-EXAONE-236B-A23B
849.6
Solar-Open-100B
262.8
Deepseek-V3.2
239.3
K-EXAONE-236B-A23B
204.9
Llama-VARCO-8B-Instruct
162.1
Grok-4.1-fast
136.4
Solar-Pro-2 (31B)(high)
107.9
Kanana-2-30B-Thinking
76.7
Kanana-2-30B-Thinking-2601
68.5
GPT-5.1 (high)
51.0
A.X-4.0 (72B)
43.3
HCX-007(high)
37.2
GPT-5.2 (high)
32.8
Claude-Opus-4.5
29.2
EXAONE-4.0.1-32B (high)
5.3

Avg Token Usage

K-EXAONE-236B-A23B
70,061
K-EXAONE-236B-A23B
41,646
Solar-Open-100B
39,496
Gemini-3-Pro-Preview
28,664
Grok-4.1-fast
20,203
Solar-Pro-2 (31B)(high)
17,442
Kanana-2-30B-Thinking-2601
15,620
Deepseek-V3.2
14,643
Kanana-2-30B-Thinking
14,612
Llama-VARCO-8B-Instruct
11,147
A.X-4.0 (72B)
6,621
GPT-5.1 (high)
6,113
Claude-Opus-4.5
5,843
HCX-007(high)
4,628
GPT-5.2 (high)
4,356
EXAONE-4.0.1-32B (high)
4,114