help asap and show all steps clearly please

$(20$ pts$)$ A parallel RL circuit is subjected to a sinusoidal voltage of frequency $4ra\frac{d}{s},$ as shown in Fig. $4.$ The currents $i_1(t)$ and $i_2(t)$ are given by $i_1(t)=10cos(4t)mA,i_2(t)=10sin(4t)mA.$

$($a$)$ Given that $i(t)=i_1(t)+i_2(t),$ write $i(t)$ in the form $i(t)=$Msin$(4t+)$; in other words, find $M$ and $.((\}$

$($b$)$ Determine the amplitude, frequency $($in Hz$),$ period $($in seconds$),$ phase shift $($in degrees$),$ and time shift $($in seconds$).(5$ pt$)$

$($c$)$ plot one cycle of the current $i(t),$ and clearly indicate the earliest time after $t=0$ at which it reaches its maximum value. $($