An exponential cancels a base-ten logarithm

Proved

WorkbookSource.problem_3709

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

lean-workbooksource-checked

The value of $10^{\log_{10}7}$ is:

Source: InternLM Lean-Workbook, record lean_workbook_3709 (Apache-2.0). The complete source proposition and explicit variable declarations are preserved.

Preamble

import Mathlib
open Real Nat

Formal statement

theorem WorkbookSource.problem_3709 : (10:ℝ)^(Real.logb 10 7) = 7  :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, record lean_workbook_3709; Apache-2.0

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