1. The problem statement, all variables and given/known data A circuit contains two elements, but it is not known if they are L, R or C. The current in this circuit when connected to a 51.0 V, 60.0 Hz source is 3.60 A and leads the voltage by 75.0 degrees. What is the impedance of this circuit? 2. Relevant equations Z=sqrt(R^2 + (Xc)^2) tan(phi)=Xc/R Xc=1/(2pifC) I=E/Z 3. The attempt at a solution I figured it contains R and C because current leads voltage, so there's no Xl. For a) Z = sqrt(R^2 + (Xc)^2), and I tried tan(phi) = Xc/R to get C for Xc = 1/(2pifC), but didn't get right answer, using phi = -75.0 degrees. Any help?