# What is the Cartesian form of (-1,(5pi)/4))?

Jan 21, 2018

The Cartesian form is $\left(\frac{\sqrt{2}}{2} , \frac{\sqrt{2}}{2}\right)$.

#### Explanation:

We can use $x = r \cos \left(\theta\right)$ and $y = r \sin \left(\theta\right)$ to convert:

$x = - 1 \cos \left(\frac{5 \pi}{4}\right) = - 1 \left(- \frac{\sqrt{2}}{2}\right) = \frac{\sqrt{2}}{2}$
$y = - 1 \sin \left(\frac{5 \pi}{4}\right) = - 1 \left(- \frac{\sqrt{2}}{2}\right) = \frac{\sqrt{2}}{2}$

So the Cartesian form is $\left(\frac{\sqrt{2}}{2} , \frac{\sqrt{2}}{2}\right)$.