Find polar coordinates (r,θ) of the point, where r>0 and 0≤θ<2π

[Dhanalakshmi]

The Cartesian coordinates of a point are given, (4,−4).

(i) Find polar coordinates (r,θ) of the point, where r>0 and 0≤θ<2π
(ii) Find polar coordinates (r,θ) of the point, where r<0 and 0≤θ<2π