How Do You Calculate Earth's Radial and Transverse Velocity Components?

[the riddick25]

Homework Statement

Find the radial and transverse components of the velocity and acceleration of the Earth, in terms of (theta) and (theta dot=d(theta)/dt)

Homework Equations

r=1/A+Bcos(theta)
Where A and B are constants given as A=0.666667x10^-11 and B=0.113333x10^-12
(theta dot)=(1/r^2)(sqrt(GM/A))

The Attempt at a Solution

I'm not quite sure how to start the problem, so if someone could give me a push in the right direction for working this question out that would be a big help.
I would prefer to work it out myself, so i am not asking for the answer, just where to start the question.

Thanks :)

 

[Delphi51]

Wouldn't the radial velocity be dr/dt and the transverse velocity r*dθ/dt ?
Just differentiate your r=1/A+Bcos(theta), the equation of motion for the Earth around the sun, to find those velocities.