I have tried using 2 method but I'm getting different answers in both methods.in the first case I assumed Vce=Vcc/2 Vcc-IcRc=Vce For maximum power transfer Vcc/(2√2)Icc/(2√2)=VccIcc/8=20W Vcc/2=IcRc RC comes out to be 1.8 But when I go for the formula (Vcc)^2/(8Rc)=20W I'm getting Rc=3.6 why is that so??