# Simple impedance calculation question

So this segment of transmission like has inductance, resistance and a capacitor in series in one of the branches. They have calculated the equivalent impedance as follows:

My question is, in the calculation of the total impedance why is the angle of the inductive reactance taken to be negative and that of the capacitive reactance taken to be positive? I thought it was supposed to be the other way around? like below:

• Where? I see Inductor <90' Capacitor <-90' – Tony Stewart Sunnyskyguy EE75 Jan 4 '17 at 8:16
• This model is flawed for the Transmission Line and does not show the shunt admittance $G+j\omega C$ Reference link? We know that a transmission line $Zt=\sqrt{\frac{R_t+j\omega L}{G_t+j\omega C}}$ – Tony Stewart Sunnyskyguy EE75 Jan 4 '17 at 14:24

It looks like a mistake to me because they use the +X$_G$ inductive reactance value near the start of the equation and thereafter, the inductive reactances are treated as negative values. It has to be a mistake or some cunning plan that the context of your question doesn't cover.