A particle moves in the plane in such a manner that its coordinates at time t are:

x=3cos((pi/4)t)

y=5sin((pi/4)t)

a)Find the length of the velocity vector at t=3

b)find the x- and y- components of acceleration of the particle at t=3

c)Find a single equation in x and y for the path of the particle

Please explain to me how to do this or possible phrase these questions better, thank you.