Theorem neghalfpire

Description: -u _pi / 2 is real. (Contributed by David A. Wheeler, 8-Dec-2018)

	Ref	Expression
Assertion	neghalfpire	⊢ - ( π / 2 ) ∈ ℝ

Proof

Step	Hyp	Ref	Expression
1		halfpire	⊢ ( π / 2 ) ∈ ℝ
2	1	renegcli	⊢ - ( π / 2 ) ∈ ℝ