Question

The cosine of a certain third quadrant angle is -0.75. Correct to 3 decimal places, what is its sine?

Answer 1

Explanation:

The x value is -.75 so you need to use the inverse to find the angle and then use sin x to find the sine.

`sin(cos^(-1)(-.75)) = .66143 = .661`

Since it is in the third quadrant, put a - sign on .661 so -.661