Chapter 10.2, Problem 5ES

In each part, a point is given in rectangular coordinates. Find two pairs of polar coordinates for the point, one pair satisfying $r\ge 0$ and $0\le \theta <2\pi ,$ and the second pair satisfying $r\ge 0$ and $-2\pi <\theta \le 0.$

$\begin{array}{l}\left(\text{a}\right)\left(-5,0\right)\\ \left(\text{b}\right)\left(2\sqrt{3},-2\right)\\ \left(\text{c}\right)\left(0,-2\right)\\ \left(\text{d}\right)\left(-8,-8\right)\\ \left(\text{e}\right)\left(-3,3\sqrt{3}\right)\\ \left(\text{f}\right)\left(1,1\right)\end{array}$