Theorem divrecd

Description: Relationship between division and reciprocal. Theorem I.9 of Apostol p. 18. (Contributed by Mario Carneiro, 27-May-2016)

	Ref	Expression
Hypotheses	div1d.1	$$⊢\phi \to A\in ℂ$$
	divcld.2	$$⊢\phi \to B\in ℂ$$
	divcld.3	$$⊢\phi \to B\ne 0$$
Assertion	divrecd	$$⊢\phi \to \frac{A}{B}=A\left(\frac{1}{B}\right)$$

Proof

Step	Hyp	Ref	Expression
1		div1d.1	$$⊢\phi \to A\in ℂ$$
2		divcld.2	$$⊢\phi \to B\in ℂ$$
3		divcld.3	$$⊢\phi \to B\ne 0$$
4		divrec	$$⊢\left(A\in ℂ\wedge B\in ℂ\wedge B\ne 0\right)\to \frac{A}{B}=A\left(\frac{1}{B}\right)$$
5	1 2 3 4	syl3anc	$$⊢\phi \to \frac{A}{B}=A\left(\frac{1}{B}\right)$$