# What is the polar form of ( 0,-2 )?

Mar 10, 2016

$\left(2 , 3 \frac{\pi}{2}\right)$

#### Explanation:

x = r cos $\theta$ = 0.
As both x and y are not 0, r is not 0.
So, cos $\theta$ = 0. $\theta = \frac{\pi}{2} \mathmr{and} 3 \frac{\pi}{2}$.

r sin $\theta$ = $- 2$.
sin $\theta = \pm 1$. So, r =$= 2 \mathmr{and} - 2$.
Both are one and the same point It is a better convention to keep r$\ge 0$.
Answer $\left(2 , 3 \frac{\pi}{2}\right) \mathmr{and} \left(- 2 , \frac{\pi}{2}\right)$