Evaluating an involutive reciprocal functional equation

Proved

WorkbookSource.problem_14193

by wamlart · Sep 12, 2026 · Mathlib 0df444a (Lean v4.33.1)

lean-workbooksource-checked

Find $f(6)$ using the equation $2f(x) + 3f\\left(\\frac{2010}{x}\\right) = 5x$

Source: InternLM Lean-Workbook, record lean_workbook_14193 (Apache-2.0). The complete source proposition and explicit variable declarations are preserved.

Preamble

import Mathlib
open Real Nat

Formal statement

theorem WorkbookSource.problem_14193 (f : ℝ → ℝ) (hf : ∀ x, 2 * f x + 3 * f (2010 / x) = 5 * x) : f 6 = 993  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_14193; Apache-2.0

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