Question #b2b3e

2 Answers
Aug 23, 2017

-1

Explanation:

We can add multiples of 2pi to (-5pi)/2 to find coterminal angles.

(-5pi)/2+2pi=-pi/2

This is located on the y-axis between Quadrant "III" and Quadrant "IV".

The point on the unit circle at this location is (0,-1), so

sin((-5pi)/2)=sin(-pi/2)=-1

Aug 23, 2017

-1

Explanation:

sin(-5 pi)/2= - sin (5pi)/2

= -sin (2pi + pi/2)

= - sin pi/2 = -1