This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.

Metamath Proof Explorer

Theorem neghalfpirx

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

Ref Expression
Assertion neghalfpirx 
|- -u ( _pi / 2 ) e. RR*

Proof

Step Hyp Ref Expression
1 neghalfpire 
 |-  -u ( _pi / 2 ) e. RR
2 1 rexri 
 |-  -u ( _pi / 2 ) e. RR*