1. The problem statement, all variables and given/known data In the circuit below, what should the value of L be at ω = 10^4 rad/s so that i(t) is in-phase with v(t)? 2. Relevant equations 3. The attempt at a solution I am a little uncertain exactly what is meant by i(t) being in phase with v(t). Do I assume that both are cosine functions, and that means that the phase angle for both of them are the same? I am not sure if I should just divide the phase voltage (unknown phase) by phase current to get the equivalent impedance? I don't know L, so it is a little tough with the expression I have for L to get something. There are no numerical values for the voltage nor current, so I mean how would I even be able to calculate an equivalent impedance with an unknown inductor value. For one I just said that L is zero for a DC current, but there must be an AC solution as well.