I need help calculating the magnitude of the impedance for a RLC circuit shown below. See the attached schematic. I found the impedance magnitude of a similar circuit here: Impedance Formulas ...see the 4th circuit from the bottom (let's call its impedance Z_a). Unfortunately, I do not know how to include the series resistance Rx into this formula. The problem I am having is whether to use the formula: Z = Rx + Z_a ...or Z = (Rx^2 + ???)^0.5 Also, I am not sure whether the value of the Rx will alter the phase angle between current and voltage of this circuit?