Ok I have the equation:

theta^2(d2R/dtheta2)+3theta(dR/dtheta)-8R=20(theta^-3)

The condition is that R=10 when theta=1

I have worked out the equation as far as the General Solution.

The C.F i got was Ae^2t + Be^-4t

I then got a General Solution of Ae^2t + Be^-4t - 4e^-3t

How do I find the values of A and B ?