Metamath Proof Explorer


Theorem relogbexpd

Description: Identity law for general logarithm: the logarithm of a power to the base is the exponent, a deduction version. (Contributed by metakunt, 22-May-2024)

Ref Expression
Hypotheses relogbexpd.1 ⊢ φ → B ∈ ℝ +
relogbexpd.2 ⊢ φ → B ≠ 1
relogbexpd.3 ⊢ φ → M ∈ ℤ
Assertion relogbexpd ⊢ φ → log B B M = M

Proof

Step Hyp Ref Expression
1 relogbexpd.1 ⊢ φ → B ∈ ℝ +
2 relogbexpd.2 ⊢ φ → B ≠ 1
3 relogbexpd.3 ⊢ φ → M ∈ ℤ
4 1 2 3 3jca ⊢ φ → B ∈ ℝ + ∧ B ≠ 1 ∧ M ∈ ℤ
5 relogbexp ⊢ B ∈ ℝ + ∧ B ≠ 1 ∧ M ∈ ℤ → log B B M = M
6 4 5 syl ⊢ φ → log B B M = M