Okay in plain english:
A capacitor is simply two metal plates with a substance in between.
A capacitor will charge up and as it charges up less and less current will flow.
An inductor resists current changes so you can change voltage really rapidly and it will maintain a relatively steady current.
So basically, inductors and capacitors have different coefficients which determine how good they are at doing their thing. So basically there is 1 frequency (with a certain bandwidth around it) that will be an equilibrium point.
I can't really explain more than that without showing you an oscilloscope or math or whatever.