# What is the Cartesian form of (-15,(-pi)/4))?

$x = \frac{- 15 \cdot \sqrt{2}}{2}$ and $y = \frac{+ 15 \cdot \sqrt{2}}{2}$

#### Explanation:

The formulas to be used are

$x = r \cdot \cos \theta$
$y = r \cdot \sin \theta$

$x = - 15 \cdot \cos \left(- \frac{\pi}{4}\right) = - 15 \cdot \frac{+ \sqrt{2}}{2} = \frac{- 15 \cdot \sqrt{2}}{2}$

and

$y = - 15 \cdot \sin \left(- \frac{\pi}{4}\right) = - 15 \cdot \frac{- \sqrt{2}}{2} = \frac{+ 15 \cdot \sqrt{2}}{2}$

God bless....I hope the explanation is useful.