Numerically solve differential equation

I have a second-order differential equation of three variables, R, θ, and τ. I don't know how I can solve this numerically for in MATLAB. The equation is below.

The equations also has these boundary conditions:

R , θ for all τ;

R = 1, = θ, where Bi is a constant, for all τ;

τ , θ for all R.

Thank you for the help!

Answer 1

[John D'Errico]

This is just a parabolic PDE, assuming that Bi is a KNOWN constant. You just say it is constant.

But you should be able to use pdepe.

help pdepe

If Bi is some unknown constant, and you expect to find a general symbolic solution, then you will need to do more work.