Series Circuit DIfferential Equation - My answer is coming out to be wrong...... 1. The problem statement, all variables and given/known data A 6.5 amp current is necessary in order to start the motor for a certain factory appliance. The circuit for the appliance is designed with a 2 ohm resistor and a 1.5 henry inductor. If there already exists a steady current of 2 amps in the circuit at time t = 0, what electromotive force is necessary to achieve the desired current in 1.25 seconds? The answer should be 15.1 volts. 2. Relevant equations 1) L di/dt + Ri = E(t) or 2) R dq/dt + q/C = E(t) 3. The attempt at a solution It makes sense to me to use Equation (1): L di/dt + Ri = E(t) 1.5 di/dt + 2i = E(t) => di/dt = [E(t) - 2i ] /1.5 => di/[E(t) - 2i] = dt/1.5 => ln[E(t) - 2i) = t/1.5 + c => E(t) = Ae-t/1.5 + 2i i(o) = 2 A = E - 4 => E(t) = (E-4)e-t/1.5 + 2i i(1.25) = 6.5 => E(t) = (E-4)e-1.25/1.5 + 13 => E - (E-4)e-0.83333 = 13 => Ee0.83333 - (E-4) = 13e-0.83333 => Ee-0.83333 - E + 4 = 29.9126 => E(e-0.83333 - 1) = 25.9126 => E = 19.9178 Ans. The answer should be 15.1 volts. PLease help!!! What is the thing that I am doing wrong!!! Thanks!!