Question

What is the reference angle and cosince of
`(7\pi )/(6)`?

Answer 1

The reference angle is π/6.

Cosine is -(√3)/2.

Explanation:

To find the reference angle, find the acute angle in quadrant I and use it as a reference for the given expression.

For the cosine, the cosine is the sine of the complementary angle. The complementary angle is the given angle beside it minus a right angle, which is exactly 90 degrees. If the angle is 25 degrees, its complementary angle will be double its amount, 50 degrees. Then, for angle angle measured "theta", the cosine is equal to the sine's right-angle subtracted by theta.