1. The problem statement, all variables and given/known data In a series circuit V = V<0 @50hz with an R and C, show that the graph of the loci or the port impedance, Z, and port admittance, Y, as the resistance R is varied from 0 to inf ohms are as shown. [URL]http://ivila.net/prob.png[/URL] [URL]http://ivila.net/loci.png[/URL] 2. Relevant equations 3. The attempt at a solution Z = R + j*X; Y = Z-1; Map to Y = G + jB (Separate Real and Complex) G = R/(R2 + X2); B = -X/(R2 + X2); G2 + B2 = 1/(R2+X2) = B/-X Then I get lost, I know I need to arrange into the format below with the condition that the R term (varying from 0 to inf) remains in the LHS, ie, out of the radius. however I am stuck . (G-x)2 + (B-y)2 = radius2 Any help would be much appreciated.