Series RLC current phasor

Use the cosine reference for phasors, i.e. a signal $A\cos(\omega t+\phi)$ maps to the phasor $A\,\angle\,\phi$. Take the loop current $i(t)$ in the passive sign convention. Find the magnitude and phase of the current phasor $\tilde{I}$ such that $i(t)=|\tilde{I}|\cos\!\left(4t+\angle\tilde{I}\right)$.