A particle is moving in the xy-plane and its position at time t is given by

$\displaystyle x=cos(\frac{\pi }{3}t)$

and $\displaystyle y=2sin(\frac{\pi }{3}t)$. When t=3 the speed of the particle is?

-Ok i know that i have to take the derivative. But i don't remember how to take the derivative of parametric equations...

all help is appreciated..