Question

Select all that have a value of 0. cos 0 sin 0

Answer 1

I just answered this question, the answers are:

cos pi/2

sin 0

tan pi

Answer 2

For cosФ×sinФ =0, then either cosФ or sin Ф must be zero. 
       cos 90 = cos 270 = 0
      sin 0 = sin 180 = sin 360 = 0.
So, the values that would give you 0 are:
1. cos 90 sin Ф
2. cos 270sin Ф
3. cos Ф sin 0
4. cos Ф sin 180 and 
5 cos Ф sin 360.