Theorem sqge0d

Description: A square of a real is nonnegative. (Contributed by Mario Carneiro, 28-May-2016)

	Ref	Expression
Hypothesis	resqcld.1	$$⊢\phi \to A\in ℝ$$
Assertion	sqge0d	$$⊢\phi \to 0\le A^2$$

Proof

Step	Hyp	Ref	Expression
1		resqcld.1	$$⊢\phi \to A\in ℝ$$
2		sqge0	$$⊢A\in ℝ\to 0\le A^2$$
3	1 2	syl	$$⊢\phi \to 0\le A^2$$