# Homework Help: Finding a constant for a partial differential equation

1. Nov 30, 2005

### KataKoniK

Can anyone help me with this question? I tried taking the derivative of u with respect to x and then summed the third derivative, but I'm getting nowhere. Any help would be great, thanks.

Let u(x1, x2, … , xn) = http://img480.imageshack.us/img480/1694/image0027hm.gif [Broken],[/URL] where a is a constant, and n is given.

Find all the values of the constant a, if any, for which the function u satisfies the partial differential equation http://img480.imageshack.us/img480/2918/image0044jl.gif [Broken] .

Last edited by a moderator: May 2, 2017
2. Dec 4, 2005

### CarlB

Do you think it's possible that you should be making a substitution for the sum of x_i squared? It just seems that polar coordinates might be an easier way to work the problem. Not that it would be easy.

Carl

Now. How do I make that little "lightbulb" that I accidentally clicked on go away?