# What is the Cartesian form of ( -9, (-7pi)/2 ) ?

(0, $- 9$)
Turn clockwise for negative angles, from $\theta$ = 0.
Here, r =$- 9$ and $\theta = - 7 \frac{\pi}{2}$.
Given point is same as $\left(- 9 , \frac{\pi}{2}\right)$. .
x = $- 9 \cos \left(\frac{\pi}{2}\right)$ =0 and y = $- 9 \sin \left(\frac{\pi}{2}\right) = - 9$