math
posted by julie .
i have a test coming up and i have no idea how to do rotations on a cartesian coordinate system. please help me!!

Let
P=(x0,y0), original position of a point P
P1=(x1, y1), position of P after rotation through an angle θ.
P1=RP
where
R=rotation matrix in two dimensional space about the origin:
cos(θ) sin(θ)
sin(θ) cos(θ)
For more information, look up:
http://en.wikipedia.org/wiki/Cartesian_coordinate_system