Theorem sqeq0i

Description: A number is zero iff its square is zero. (Contributed by NM, 2-Oct-1999)

	Ref	Expression
Hypothesis	sqval.1	|- A e. CC
Assertion	sqeq0i	|- ( ( A ^ 2 ) = 0 <-> A = 0 )

Proof

Step	Hyp	Ref	Expression
1		sqval.1	|- A e. CC
2		sqeq0	|- ( A e. CC -> ( ( A ^ 2 ) = 0 <-> A = 0 ) )
3	1 2	ax-mp	|- ( ( A ^ 2 ) = 0 <-> A = 0 )