Hyperbolic Simplification



Dear Sir,
 If you want to use the demoavre identity of exp(i)+exp(-i)=2cos(0)
we can use:             trigrat(exp(%i)+exp(-%i));

But on the other hand if you want the hyperbolic identity, 
exp(1)+exp(-1)=2cosh(0)
Why does this not implemented?
I think it is much like the previous trigonimetric example{especially 
that the documentation says that trigonometric fns are sin, cos, sinh, 
cosh,.... }
Unfortunately, I don't have time to learn Lisp, I went to trigrat fn in 
my share folder and there was .mac and .lisp.

Thanks

Mohamed Abouzied