Metamath Proof Explorer


Theorem sinhalfpi

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

Ref Expression
Assertion sinhalfpi sinπ2=1

Proof

Step Hyp Ref Expression
1 sinhalfpilem sinπ2=1cosπ2=0
2 1 simpli sinπ2=1