TRIGONOMETRIC IDENTITIES AND EQUATIONS

(a) Trigonometric Identities:

An equation is a statement of equality between to expressions.  A trigonometric equation is an equation containing one or more trigonometric ratios.  This is different from a trigonometric identity, which is a special type of equation, which are not solved, but rather proven to be true.   When proving these identities, it is best to change all ratios into sines and cosines.

(b) The Double Angle Formula:

(d) Amplitude, Period, Phase Shift: 

Amplitude: maximum displacement from the x -axis
Period: length along the x-axis required for one complete cycle.
Phase Shift: a displacement left or right along the x-axis
Vertical displacement: a displacement up or down the y-axis.

Variable:                       Effect:

a                                  amplitude
b                                  period
c                                  phase shift
d                                  vertical displacement

[ Home ] [ Up ]