Can anyone please give me some idea for this problem?

The instantaneous power, p, in an electric circuit is given by p = iv,

where v is the voltage and i is the current.

Calculate the maximum value of power in the circuit if v=0.02 sin(100 pi t)volts and i=0.6 sin(100pi t+ pi/4 ) amp

Calculate the first time that the power reaches a maximum value.