Convert the rectangular coordinate (2,-2) to polar form and find two additional representations of this point.

Question

Can you check my work and explain how to finish the question?

r=√(2)2+(-2)2
r=2√2

tan theta = (-2)/2
theta = -1

polar coordinate= (2√2, -1)

Answer 1

no,
tanØ = -1 , not Ø = -1

since (2,-2) is in quadrant IV, Ø = 315° or 7π/4

so one answer is (2√2 , 7π/4)
another would be (-2√2, 3π/4)