TRIGONOMETRY FOR STATICS
For 0o and 90o: These functions are limiting values that can be observed from the drawing. As side y approaches 0 (zero), the x approaches r.
For 30o and 60o:
Identities in terms of tan (q/2):
The sine function is an odd function since
The cosine function is an even function since
The tangent function is an odd function since
As a close approximation, when an angle(expressed in radians) is very small, we may use the following approximations