# Precalculus SOH CAH

posted by
**Greg**
.

how are the following relations true? S(theta + pi/2) = C(theta) and C(theta + pi/2) = -S(theta)?

posted by
**Greg**
.

how are the following relations true? S(theta + pi/2) = C(theta) and C(theta + pi/2) = -S(theta)?