durance

Can someone please help me with this problem: a) Try to decide the transfer function H(jω) for this: http://yfrog.com/7cfunknj vin(t)=Acos(ωt) H(jω) =Vout/Vin I have count that C and R2 to R2/(jωR2C+1) From here I dont know what to do b) What is H(jω) if A->∞ thanks in advance