How is the equation for impedance in a parallel resonance LC circuit derived?

[uzair_ha91]

"At resonance frequency, the circuit impedance is maximum. It is resistive and its value is given L/Cr..."
The book doesn't explain how impedance equals L/Cr, so I'm confused here. How is it derived? (Can you please show all the steps?)
Thanking in advance...

 

[berkeman]

"At resonance frequency, the circuit impedance is maximum. It is resistive and its value is given L/Cr..."
The book doesn't explain how impedance equals L/Cr, so I'm confused here. How is it derived? (Can you please show all the steps?)
Thanking in advance...

This resource should help you out:

http://en.wikipedia.org/wiki/RLC_circuit

.

 

[uzair_ha91]

Sorry , the article does not have that equation nor any explanation regarding that...

 

[uzair_ha91]

I googled it and found the closest result here, but again not explained where the equation was derived from: http://www.hobbyprojects.com/phasors_and_resonance/parallel_resonance_in_AC_circuits.html