Date: Aug 21, 2013 2:46 AM
Author: Torsten
Subject: Re: PDE - spherical coordinates question (polar)
"Saad" wrote in message <kuvtva$guv$1@newscl01ah.mathworks.com>...

> Hi,

> I'm trying to solve the following PDE using (pdepe).

> Does anyone have any tips on how to input the variable coefficients for this equation.

>

> dH/dt + 1/sinx d/dx(H^3 (sinx)^2)=0

>

>

> Thanks,

> Saad

pdepe is suited for PDEs which contain a second-order spatial derivative (in your case, this would be an expression involving d^2H/dx^2).

Since your equation is a first-order PDE, you will have to solve it using a different tool.

Differentiating out, you get

dH/dt + 3*H^2*sin(x)*dH/dx = -2*H^3*cos(x).

Best wishes

Torsten.