Expressing polar unit vectors in Cartesian coordinates

[v_pino]

Homework Statement

Give the equations for the plane polar unit vectors

^ ^
r and (theta)
- -

in terms of

the Cartesian unit vectors
^ and ^ and hence show that
i j
- -

^ . ^
dr / dt = (theta) x theta
- -

Homework Equations

The Attempt at a Solution

I don't know how I can approach this question as I missed my lesson. I tried to google Polar Coordinates but the materials that I found weren't closely related to this. What topic should I look up? Any recommended websites? Thanks!

 

[kuruman]

You will find what you need here

http://en.wikipedia.org/wiki/Polar_coordinate_system

then take derivatives remembering the product and chain rules of differentiation.