Question

Which inverse trigonometric function will NOT determine the measurement of angle A? sin-1(0.6) cos-1(1.25) tan-1(0.75)

Answer 1

cos-1(1.25)

Explanation:

cos-1 (also call arccos) is the inverse function of the cosine function. If a cosine is given, cos-1 determine which angle gives that cosine. However, cosine function has a range between -1 and 1, so, it is impossible that a cosine of a given angle is equal to 1.25, and therefore, cos-1(1.25) doesn't exist.