Feature request: cosh(asinh(x)) = sqrt(x^2+1)



Robert Dodier wrote:
> On 1/20/08, Jan Bessai <jan.bessai at tu-dortmund.de> wrote:
> 
>> Maxima is able to differentiate asinh(x) correctly, but does not know
>> the equation cosh(asinh(x)) = sqrt(x^2 + 1) (at least not in 5.13.0)
>> which is usually needed to do that.
> 
> tellsimpafter as mentioned by Barton is one way to implement that Identity.
> Here is another way.

This begs the question:  Should maxima already know this and if so, how 
should it be done?  I think it would be easy to add this rule in 
trigo.lisp, but is that the right thing to do?

Ray