1. The problem statement, all variables and given/known data The current in a 25mH inductor is known to be - 10A for t <= 0 and (-10cos400t - 5sin400t)e^-200t A for t >= 0. Assume the passive sign convention. Part A: At what instant of time is the voltage across the inductor maximum? Part B: What is the maximum voltage? 2. Relevant equations V=L*di/dt 3. The attempt at a solution I took the derivative of (-10cos400t - 5sin400t)e^-200t, then took the derivative again, set to zero, and found the value of t at that point. 5000*e^(-200t)*sin(400t) 1000000*e^(-200t)(2cos400t - sin400t) = 0 @ t = 0.01339 s Where am I going wrong? Am I missing something?