Question

HELP on eigenfrequencies??

A rectangular drum is 0.1m x 0.1m. It is stretched to a tension of 50 Nm^(-1), and its mass is 0.02kg.
Determine all eigenfrequencies in the frequency range 0 to 700 s^(-1). Mark their position along the omega-axis.

(Let W = omega)
The equation I have been given is W_mn = c ( (mpi/a)^2 + (npi/b)^2 ) ^(1/2)

I worked out that the area = 0.01m^2.
Mass per unit area = 0.02kg/0.01m^2 = 2kgm^(-2).

I don't understand what a, b and c are, and also m and n.

I feel as if I can do it, but I'm confusing myself. Help would be GREATLY appreciated!