Solve the equation : l di/dt + ri(t) + 1/c ∫t i(τ) dτ = e(t), subject to i(0) = 0, with l, r, c, and e(t) as given. l = 0.1 H, r = 3 Ω, c = 0.05 F, e(t) = 90(t - 1) - (t - 2).