40. An RL circuit includes a voltage source , a resistor , and an inductor H, as shown in the figure. The differential equation that describes the response of the circuit is where is the current in the inductor. Initially , and then at the voltage source is changed. Determine the response of the circuit for the following three cases:

(a) V for .

(b) V for .

Each case corresponds to a different differential equation. The solution is the current in the inductor as a function of time. Solve each case for s. For each case plot and versus time (make two separate plots on the same page).