Sections:

Trigonometric Identities and Equations, Page 6

ExamplesMath books 5.3.6

Let’s use the identities you just learned about to try some examples.

Example 1:

If secant of theta = 3/2, find cottheta.

tan^2 (theta) + 1 = sec^2 (theta); tan^2 (theta) + 1 = (3/2)^2; tan^2 (theta) = 9/4 - 1; tan^2 (theta) = 5/4; tan(theta) = + or - square root of 5/4; tan(theta) = + or - root 5 divided by 2; cot(theta) = 1/tan(theta); cot(theta) = + or - 1/ (sqrt(5)/2) = + or - 2/sqrt(5) * sqrt(5)/sqrt(5) = + or - 2sqrt(5)/5