The polar coordinates equivalent to (−3,3) are

r=x2+y2=9+3=23α=tan−1|y||x|α=tan−1(33)α=tan−1(13)=π6Point (−3,3) lies in the second quadrant. ∴θ=π−α=π-π6=5π6So, polar coordinates are (23,5π6)