Question

For which value of 0 is sin0=-1:

A. Pi/2
B. Pi
C. 3Pi/2
D. 2Pi

Answer 1

C. 3Pi/2 or 270 degrees

Explanation:

The first step is to ignore the negative sign and then evaluate the arcsin of 1 to obtain the reference angle of θ in the first quadrant;

θ = arcsin(1)

θ = 90 degrees or equivalently pi/2

Since the sine of θ was given as -1, this will imply that θ lies either in the third or forth quadrant where the sine of an angle is negative.

To obtain the value of θ in the third quadrant we simply add 180 degrees of pi radians to our reference angle;

90 + 180 = 270 degrees

pi/2 + pi = 3/2 pi