Current in an AC circuit is given by $i=3\sin \omega t+4\cos \omega t$ then

$I=5\sin \left(wt+{53}^{\circ }\right)$

$I_{\circ }=5\mathrm{A}$

$I_{RMS}=\frac{I_{\circ }}{\sqrt{2}}=\frac{5}{\sqrt{2}}A$

Mean value of current in positive half cycle 

$\frac{2}{\pi }{I}_0=\left(\frac{2}{\pi }\right)s=\frac{10}{\pi }A$

If voltage applied is $V=V_m\sin \omega t$, it means the current is leading the voltage. Hence the circuit may contain resistance and capacitance.

If voltage applied is $V=V_m\cos \omega t$, it means the current is lagging behind the voltage. Hence the circuit can may contain resistance and inductance.