Theorem sqnegd

Description: The square of the negative of a number. (Contributed by Igor Ieskov, 21-Jan-2024)

	Ref	Expression
Hypothesis	sqnegd.1	$$⊢\phi \to A\in ℂ$$
Assertion	sqnegd	$$⊢\phi \to {\left(-A\right)}^2=A^2$$

Proof

Step	Hyp	Ref	Expression
1		sqnegd.1	$$⊢\phi \to A\in ℂ$$
2		sqneg	$$⊢A\in ℂ\to {\left(-A\right)}^2=A^2$$
3	1 2	syl	$$⊢\phi \to {\left(-A\right)}^2=A^2$$