why\(sin \theta =-1 \)
then the ans is \(\theta =3 \pi /2\)?
If you look at the unit circle, the angle of 3pi/2 has its terminal point at (x. y) = (0, -1)
And sin = y/r and r = 1 on the unit circle.....so ..... sin (3pi/2) = y / r = -1 1 = -1
