Answer
$W_{source}=0\ J.\ \ \ \ \ -\infty10$
Work Step by Step
The energy across the source is equal to sum of energies across the elements
$W_{source}=W_{R}+W_{L}$
from problem 4.4, the energy across the inductor was found to be
$W_{L} = 0 J \ \ \ \ \ \ -\infty10$
Find the power across the resistor
$P_{R}=i(t)\times V_R(t)=i(t)\times i(t)/R=i(t)^2/R=i(t)^2/R=i(t)^2/(1)=i(t)^2$
Find the energy across the resistor for $-\infty10$
$W_{R}=\int_{-\infty}^{t} P_R \ dt=\int_{-\infty}^{t} i(t)^2\ dt = \int_{-\infty}^{0}0\ dt+\int_{0}^{10}t^2\ dt+\int_{10}^{t} 100\ dt$
$=\frac{1}{3}t^3|_0^{10}+100t|_{10}^t=\frac{1000}{3}+100t-1000=100t-\frac{2000}{3}\ J$
Find the energy across the source for $-\infty
