thank you for the hint Russell,
but that's not a solution to my problem, as I want to write the quantity
Cosh(x)*Cosh(y)
ONLY in function of k. If I did like you suggested me, I find terms like
Sinh(x)+Sinh(y)
and I can't find a way to write them in function of k.
Given the quantity
Cosh(x)*Cosh(y)
where x and y are two indipendent real variables is it possible to write it only in function of
k=Cosech(x)*Cosech(y)
?
It could seem a quite easy problem but I spent a few days between the proprieties of hyperbolic functions and I really...