Trig and trig functions

Period

= 1 cycle

cosine graph

starts at 1, goes down to 0 (at pi over 2), goes to -1 (at pi)

sine wave

One in which amplitude varies in proportion to the sine function of an angle.

Periodic functions

a function with a pattern that repeats exactly throughout its domain

Radian

a unit of angle, equal to an angle at the center of a circle whose arc is equal in length to the radius.

trig function equation

amplitude is ALWAYS positive