# What is the distance between the following polar coordinates?:  (-1,(pi)/2), (2,(15pi)/12)

Mar 11, 2018

I left explanation, try to finish it

#### Explanation:

In Euclidean geometry, we have where dl is the distance, we have:
${\mathrm{dl}}^{2}$ = ${\mathrm{dx}}^{2} + {\mathrm{dy}}^{2}$

In polar coordinates:
x =$r \cdot \cos \left(\theta\right)$
dx = $\mathrm{dr} \cos \left(\theta\right) - r \sin \left(\theta\right) d \theta$

y = $r \cdot \sin \left(\theta\right)$
dy = $\mathrm{dr} \sin \left(\theta\right) + r \cos \left(\theta\right) d \theta$

Plug into the first formula and you get the answer:)

Distance between 2 coordinates in polar coordiantes is given by:
l = $\sqrt{{\left({r}_{2} - {r}_{1}\right)}^{2} + {r}^{2} \left({\theta}_{1} - {\theta}_{2}\right)}$