Question

find two values of (theta) for which sin(theta)= 0

Answer 1

If you look at a graph of y = sin (x), you will see that the sine curve hits zero every 180 degrees starting at the origin. (x is the same as saying theta)


So, two places where sin (theta) = 0 would be:
theta= 0 degrees (0 radians)
theta = 180 degrees (pi radians)