1. The problem statement, all variables and given/known data The voltage across and current through a device are given by: v(t)= 5cos(4∏t)V i(t) = 0.1cos(4∏t)A determine the instantaneous power p(t) at t=0 and t = 0.25s 2. Relevant equations p=vi 3. The attempt at a solution for t=0 I got p=0.5W for t=0.25 I got p = 0.5W the textbook says at t=0 it should be 0. Does power always equal 0 at t=0 or did i mess up on my calculation?