The variation of pressure with density

The variation of pressure with density in a thick gas layer is given by P = Cpn, where C and n are constants. Noting that the pressure change across a differential fluid layer of thickness dz in the vertical z-direction is given as dP = – pg dz, obtain a relation for pressure as a function of elevation z. Take the pressure and density at z = 0 to be P0 and r0, respectively.