I have come across the following equation while reading about the Unruh Effect in Black Hole Physics. . K is a function of $x,y,\rho,t$ i.e $K=K(x,y,\tau, \rho)$. $\omega, k,m$ are constants. $$\rho^2 \frac{\partial^2 K}{\partial \rho^2}+\omega^2 \frac{\partial^2K}{\partial \tau ^2}-k^2 \rho^2 (\frac{\partial^2 K}{\partial x^2}+\frac{\partial^2K}{\partial y^2})-\rho^2m^2K=0$$
How do I solve it?