Question: How to get exact value of hyperbolic functions without "EVALF"

Guys, really need your help!

I'm carrying out some computations on my recent project. The final aim is to obtain a 2-D Graph. The function depends on an integral with floating limit, which depends on the variable of the graph.

that looks like

plot( FunctionOf(int(F(x,z), x=arccosh(z)...0)), z=1..2)

And I'm facing the following problem: "arccosh" is a kind of hyperbolic functions which value can be determined just by function "evalf"; that is why while having variable of a view "arccosh(z)" the program does not manage to plot graph, "Evalf" does not help either, as "z" is unknown variable till the very last computation of the graph and the program does not cope with the problem.

So, is there any way to make maple evaluate hyperbolic functions instead of writing the premise? I mean how can I get all the time  arccosh(3)--->1.7675 instead of getting arccosh(3)---->arccosh(3) WITHOUT EVALF FUNCTION!!!

PLEASE HELP!!!!