Converting from admittance to impedance

The GB plane is, as you have seen, similar in appearance to the RX plane, although mathematically the two are worlds apart. Once you’ve found a complex admittance for a parallel RLC circuit, how do you transform this back to a complex impedance? Generally, it is the impedance, not the admittance, that technicians and engineers work with.
The transformation from complex admittance, or a vector G+jB, to a complex impedance, or a vector R + jX, requires the use of the following formulas:

If you know the complex admittance, first find the resistance and reactance components individually. Then assemble them into the impedance vector, R + jX.