I think I am making a silly error:
They say: "we know the angle arcsin((radical3)/2) equals the angle between [-pi/2,pi/2] who sine is (radical3)/2
This angle is 60 radians
Apparently 60 is wrong, but I thought sin60 is radical3/2. Are they asking for the values of arcsin60? Amateur question but I'm confused as to what they want.