Let r= 3-3 sin θ

How do I test for symmetry θ = π/2?

test for two angles PI/2+e, and PI/2 -e

use the formulas for sum and difference

1. r= 3-s(PI/2+e)
= 3-[2sinPI/2 sin e]
= 1-2 sin(e)

2. r= 3-s(PI/2 -e)
r= 3-2sin(-e)
r= 3+2sin(e)

so is it symmetrical?