Posted by ashely on Saturday, February 11, 2012 at 1:14pm.
write down the equation d^2u/dt^2=c^2 grad^2u in a plane polar coordinates .by the method of separation of variables , reduce the PDE to obtained to a set of ODE's

maths  Steve, Saturday, February 11, 2012 at 5:41pm
a web search on
second order partial differential equations polar coordinates
will turn up several useful articles on the Laplace operator in polar coordinates.