## Help me get Cu in terms of other variables

Hi,
Attached are the formulas which describe the operation of an Capacitance meter. There are three formulas based on the resonant frequency of a parallel LC circuit. I tried very hard to derive them to get the equation written at the end but it was useless. Although I managed to get an equation involving only Cu, Ccal and F's ... when I tried to match by inserting simple values I did not have success. I am sure of the last formula because I tested it with strange values (C=5, Ccal=3, L=7 and Cu=9) and I got the correct Cu value. Can anyone give me some hints how to get there? thanks