Problem Analysis #18

17.32s
3,114 toks
Problem Statement

Let R\mathbb{R} denote the set of all real numbers. Let f:RRf: \mathbb{R} \to \mathbb{R} be a function such that f(x)>0f(x) > 0 for all xRx \in \mathbb{R}, and f(x+y)=f(x)f(y)f(x + y) = f(x)f(y) for all x,yRx, y \in \mathbb{R}.Let the real numbers a1,a2,,a50a_1, a_2, \ldots, a_{50} be in an arithmetic progression. If f(a31)=64f(a25)f(a_{31}) = 64f(a_{25}), andi=150f(ai)=3(225+1),\sum_{i=1}^{50} f(a_i) = 3(2^{25} + 1),find the value ofi=630f(ai).\sum_{i=6}^{30} f(a_i).\

Ground Truth
96
Execution Trace
Reasoning Process

[THOUGHT] I'll model the sequence (f(a_i)) as a geometric progression using the functional equation and arithmetic progression structure, then use the given conditions to find the common ratio and first term. Finally, I'll compute the required partial sum using Python for exact arithmetic. [/THOUGHT] [PYTHON] from fractions import Fraction

Given: r^6 = 64 and r>0, so r = 2

r = 2

Let f(a_i) = c * r^(i-1); sum i=1..50 equals 3(2^25 + 1)

from math import isclose

S50 = 3 * (225 + 1) c = Fraction(S50, 250 - 1) # exact rational

Sum from i=6 to 30 of f(a_i) = c * sum_{k=5}^{29} r^k = c * 2^5 * (2^25 - 1)

S_6_30 = c * (25) * (225 - 1)

print("c =", c) print("Sum i=6..30 =", S_6_30) print("As integer:", int(S_6_30)) [/PYTHON]

Tool Output
[PYTHON OUTPUT] c = 3/33554431 Sum i=6..30 = 96 As integer: 96 [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] Using the Python-verified geometric progression parameters, the required partial sum from (i=6) to (30) is 96. [ \sum_{i=6}^{30} f(a_i) = 96 ] [/THOUGHT] \boxed{96}

Final Model Output
96

Comparative Analysis (P18) (Average across runs)

Avg Time Taken

Llama-VARCO-8B-Instruct
103.6
Gemini-3-Pro-Preview
52.0
Solar-Pro-2 (31B)(high)
48.8
Deepseek-V3.2
38.6
HCX-007(high)
32.0
A.X-4.0 (72B)
31.1
Grok-4.1-fast
27.7
Claude-Opus-4.5
22.0
GPT-5.1 (high)
17.3
EXAONE-4.0.1-32B (high)
5.7

Avg Token Usage

Solar-Pro-2 (31B)(high)
9405.0
Grok-4.1-fast
7425.0
Gemini-3-Pro-Preview
6113.0
Deepseek-V3.2
5286.0
Claude-Opus-4.5
5158.0
HCX-007(high)
4565.0
EXAONE-4.0.1-32B (high)
4213.0
Llama-VARCO-8B-Instruct
3600.0
GPT-5.1 (high)
3114.0
A.X-4.0 (72B)
2654.0