I am still trying to solve this but I first, I need someone to explain to me about the sum of the currents, which I don't understand. The phasor of current I1 is 2+3j[A], and the phasor of current I2 is 1[A]. 1) Find the value of impedance Z. 2) Let the phase difference (arg(I3/I4)) between I3 and I4 be θ. Find the value of tan θ. Ok, firstly, I am told that I1 = I2 + I3. My question is, what happened to I4?