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