[Maxima] Feature request: cosh(asinh(x)) = sqrt(x^2+1)
robert.dodier at gmail.com
Mon Jan 21 18:58:01 CST 2008
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.
defrule (r1, cosh(asinh(x)) , sqrt(x^2 + 1));
Now the rule r1 is applied only when specifically requested
(while tellsimp / tellsimpafter rules are always applied).
apply1 (%, r1);
If you have a collection of identities r1, r2, r3, ... you could make up
a function to apply all of them, e.g.
simplify_hyperbolic_fcns (expr) := apply1 (expr, r1, r2, r3, ...)
Note the function to apply rules is named apply1.
There is also a function "apply" which is different.
Hope this helps,
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