Theorem sinhalfpi

Description: The sine of _pi / 2 is 1. (Contributed by Paul Chapman, 23-Jan-2008)

	Ref	Expression
Assertion	sinhalfpi	|- ( sin ` ( _pi / 2 ) ) = 1

Proof

Step	Hyp	Ref	Expression
1		sinhalfpilem	|- ( ( sin ` ( _pi / 2 ) ) = 1 /\ ( cos ` ( _pi / 2 ) ) = 0 )
2	1	simpli	|- ( sin ` ( _pi / 2 ) ) = 1