For an ideal brayton cycle on a cold air-standard basis show that (a) the back work ratio is given by bwr t1/t4 where t1 is the temperature at the compressor inlet and t4 is the temperature at the turbine exit. (b) the temperature at the compressor exit that maximizes the net work developed per unit of mass flowing is given by t2 1t1t321/2 where t1 is the temperature at the compressor inlet and t3 is the temperature at the turbine inlet.