It can be shown that the thermal efficiency of a combined gas-steam power plant ï¨cc can be

Question:

It can be shown that the thermal efficiency of a combined gas-steam power plant ï¨cc can be expressed in terms of the thermal efficiencies of the gas- and the steamturbine cycles as

Prove that the value of ï¨cc is greater than either of hg or ï¨s. That is, the combined cycle is more efficient than either of the gas-turbine or steam-turbine cycles alone.