Theorem neghalfpirx

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

	Ref	Expression
Assertion	neghalfpirx	$$⊢-\frac{\mathrm{\pi }}{2}\in {ℝ}^{*}$$

Proof

Step	Hyp	Ref	Expression
1		neghalfpire	$$⊢-\frac{\mathrm{\pi }}{2}\in ℝ$$
2	1	rexri	$$⊢-\frac{\mathrm{\pi }}{2}\in {ℝ}^{*}$$