Deriving the 3D Wave Equation: A Comprehensive Explanation

[Tuneman]

I would like to know how to derive the wave equation for a 3 dimensional case, I was looking it up on wikipedia, and their explanation wasn't very comprehensive, I was wondering if anyone knew of any other website that would be able to let me fullly understand it.

Edit: not the shrodinger wave equation, but general case of a wave.

 

[es]

Not sure what you mean by 3 dimensional case but I think it is just a definition. If you see an equation of the form U_tt = U_xx + U_yy + U_zz we choose to call it the wave equation in three dimensions.