# What is the Cartesian form of ( -6 , ( - 9pi)/2 ) ?

Nov 2, 2017

$\left(0 , 6\right)$

#### Explanation:

It can be seen from the diagram that the x coordinate of P is $r \cos \left(\theta\right)$ and the y coordinate of P is $r \sin \left(\theta\right)$

So:

$x = r \cos \left(\theta\right)$

$y = r \sin \left(\theta\right)$

From example:

$x = - 6 \cos \left(\frac{- 9 \pi}{2}\right) = 0$

$y = - 6 \sin \left(\frac{- 9 \pi}{2}\right) = 6$

So Cartesian coordinate is:

$\left(0 , 6\right)$