Metamath Proof Explorer


Theorem rerecid2d

Description: Multiplication of a number and its reciprocal. (Contributed by SN, 25-Nov-2025)

Ref Expression
Hypotheses sn-rereccld.a ⊢ φ → A ∈ ℝ
sn-rereccld.z ⊢ φ → A ≠ 0
Assertion rerecid2d ⊢ φ → 1 / ℝ A ⁢ A = 1

Proof

Step Hyp Ref Expression
1 sn-rereccld.a ⊢ φ → A ∈ ℝ
2 sn-rereccld.z ⊢ φ → A ≠ 0
3 1 2 sn-rereccld ⊢ φ → 1 / ℝ A ∈ ℝ
4 1 2 rerecidd ⊢ φ → A ⁢ 1 / ℝ A = 1
5 1 3 4 remulinvcom ⊢ φ → 1 / ℝ A ⁢ A = 1