Trigonometric Identities Worksheet.

There are numerous trig identities, many of them very basic. You should know these since they appear frequently:

horizontal shifts.

sin (-x) = -sin x, cos (-x) = cos x, tan (-x) = -tan x symmetries.

pythagorean identities.

double angle identities.

Use any appropriate methods to prove the following identities.

1.

2.

3.

4.

Completely solve for x over the given intervals.

5. 2cos² x + cos x - 1 = 0, 0 £ x £ 2p

6. cos (2x) = cos x, 0 £ x £ 2p