[R] How can I fitting this function from values.

[Horacio Castellini]

Hi all, I'd like fit this function:

G(t)=A*1/(1+t/B)*1/sqrt(1+t/C)

where A, B and C are fitting constants that one like search. I have
got a fcs<-(t,G(t)) value table in a data frame.

Any one can help me? Tahnks Horacio.