How basic trigonometric identities are used? A tutorial with Several examples with detailed solutions are presented. A list of the basic Trigonometric Identities
x is an angle in quadrant III and sin x = -1 / 3. Find cos x.
Solution to Example 1:
As an exercise, use the value of sin x given above and cos x found to check that sin2x + cos2x = 1.
x is an angle in quadrant IV and tan x = -5. Find sin x.
Solution to Example 2
Simplify the trigonometric expression
Solution to Example 3