find the points of horizontal and vertical tangency (if any) to the polar curve.

r=1-sin theta

i got horizontal tangent at (1/2, pi/6) (2, 3pi/2) (1/2, 5pi/6)

and vertical tangent at (3/2, -pi/6) (3/2, 7pi/6)

can anyone check my work and see if those are correct? i am not sure about the vertical tangent points...

thanks a bunch