Theorem sqmuld

Description: Distribution of square over multiplication. (Contributed by Mario Carneiro, 28-May-2016)

	Ref	Expression
Hypotheses	expcld.1	⊢ ( 𝜑 → 𝐴 ∈ ℂ )
	mulexpd.2	⊢ ( 𝜑 → 𝐵 ∈ ℂ )
Assertion	sqmuld	⊢ ( 𝜑 → ( ( 𝐴 · 𝐵 ) ↑ 2 ) = ( ( 𝐴 ↑ 2 ) · ( 𝐵 ↑ 2 ) ) )

Proof

Step	Hyp	Ref	Expression
1		expcld.1	⊢ ( 𝜑 → 𝐴 ∈ ℂ )
2		mulexpd.2	⊢ ( 𝜑 → 𝐵 ∈ ℂ )
3		sqmul	⊢ ( ( 𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ ) → ( ( 𝐴 · 𝐵 ) ↑ 2 ) = ( ( 𝐴 ↑ 2 ) · ( 𝐵 ↑ 2 ) ) )
4	1 2 3	syl2anc	⊢ ( 𝜑 → ( ( 𝐴 · 𝐵 ) ↑ 2 ) = ( ( 𝐴 ↑ 2 ) · ( 𝐵 ↑ 2 ) ) )