The current source shown above is a $3$ Amp pulse: $I_S=3u(t)-3u(t-0\mathrm{.}003).$

a$.$ Find the currents $i_L(t)$ for $t>0$ then deduce $i_R(t)$ for $t>0.$ Find $i_R(0\mathrm{.}003).$ Express your answers in unit step format.

h$.$ Find $i_R(0\mathrm{.}003)$ and $i_R(0\mathrm{.}004)$