How do polar coordinates work?

Question

shamim · Answer

ur question is not clear to me

shamim · Answer

i know    x=rcos(theta)
               y=rsin(theta)

shamim · Answer

if u wanna ask me more then i m ready to reply

anonymous · Answer

first consider a point, P, on the x-y-plane. Draw a line fro the point to the origin. Now draw a line from the point to the x-axis, this line being perpendicular  to the x-axis. Where this line intersects the x-axis is the x coordinate. We could do the same for the y-axis and we would get the y-coordinate.

Now instead of doing that imagine we have a line( coincident with  the x-axis for sale of argument). This line can rotated around the origin. Rotate it till the line is in a position such that P is on the line. The line makes an angle  theta with the x-axis (original line). 
Now to specify the point P we need only say rotate the line through theta and move (form the origin a distance |OP| along the line.

Now move P and the and the angle and the distance from the origin change. So instead of using X and Y coordinates we can use the angle theta and the distance from the origin (call this r).