# How do you find the corresponding rectangular coordinates for the point  (-1, (-3pi)/4 )?

Jan 23, 2018

The rectangular 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:

$x = - 1 \cos \left(- \frac{3 \pi}{4}\right) = - 1 \left(- \frac{\sqrt{2}}{2}\right) = \frac{\sqrt{2}}{2}$
$y = - 1 \sin \left(- \frac{3 \pi}{4}\right) = - 1 \left(- \frac{\sqrt{2}}{2}\right) = \frac{\sqrt{2}}{2}$

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