$9\mathrm{.}1$ Given the sinusoidal voltage $v(t)=50cos(30t+10)V,$ find: $($a$)$ the amplitude

$($b$)$ What is the $V_m,($b$)$ the period $T,($c$)$ the frequency $f,$ and

$($d$)v(t)$ at $t=10ms.$

$($c$)$ Find the

$($d$)$ Calculate $i,$