α = cos-1(A.B/AB). What is the range of α? A. 0˚<α<90˚

a-cos-1-a-b-ab-what-is-the-range-of-a-a-0-a-90

α = cos-1(A.B/AB). What is the range of α?

A. 0˚<α<90˚

B. 0˚<α<180˚

C. 90˚<α<180C

D. 0˚<α<45˚

I have been asked this question in an internship interview.

My question comes from Dot Product and Cross Product topic in portion Force Vectors of Engineering Mechanics

The correct answer is B. 0˚<α<180˚

Explanation: Cosine inverse function is defined only between 0˚ to 180˚. It cannot be defined under any of the given range, because this is the principle range of the inverse cosine function.