Theorem msqge0i

Description: A square is nonnegative. (Contributed by NM, 14-May-1999) (Proof shortened by Andrew Salmon, 19-Nov-2011)

	Ref	Expression
Hypothesis	lt2.1	$$⊢A\in ℝ$$
Assertion	msqge0i	$$⊢0\le AA$$

Proof

Step	Hyp	Ref	Expression
1		lt2.1	$$⊢A\in ℝ$$
2		msqge0	$$⊢A\in ℝ\to 0\le AA$$
3	1 2	ax-mp	$$⊢0\le AA$$