Metamath Proof Explorer


Theorem div1

Description: A number divided by 1 is itself. (Contributed by NM, 9-Jan-2002) (Proof shortened by Mario Carneiro, 27-May-2016)

Ref Expression
Assertion div1 ⊢ A ∈ ℂ → A 1 = A

Proof

Step Hyp Ref Expression
1 mullid ⊢ A ∈ ℂ → 1 ⁢ A = A
2 ax-1cn ⊢ 1 ∈ ℂ
3 ax-1ne0 ⊢ 1 ≠ 0
4 2 3 pm3.2i ⊢ 1 ∈ ℂ ∧ 1 ≠ 0
5 divmul ⊢ A ∈ ℂ ∧ A ∈ ℂ ∧ 1 ∈ ℂ ∧ 1 ≠ 0 → A 1 = A ↔ 1 ⁢ A = A
6 4 5 mp3an3 ⊢ A ∈ ℂ ∧ A ∈ ℂ → A 1 = A ↔ 1 ⁢ A = A
7 6 anidms ⊢ A ∈ ℂ → A 1 = A ↔ 1 ⁢ A = A
8 1 7 mpbird ⊢ A ∈ ℂ → A 1 = A