If you don't already know, this is an equivalent to conductance. What I can't figure out is why reactance (X) would have any place in this equation? Remember, we're talking about conductance here, not susceptance. In an equation for susceptance it would make sense... being that it's comprised of both resistive and reactive parts... but in an equation for conductance (which is also equal to 1 / R remember) I just don't understand how it could be derived. What am I missing here? Again the equation is G = R / R^2 + X^2 Here's a link to Wikipedia's page on Admittance. This equation is near the top under the header "Conversion from impedance to admittance". Thanks in advance for anyone who shares their thoughts on this.