Re: 'demoivre' not quite up to Wolfram's 'ExpToTrig' ?

A moment ago, I removed the debugging print statement:

%i3) exponentialize(sinh(x));
(%o3) (%e^x-%e^-x)/2

(%i4) function_convert(exp=hyperbolic, %);
(%o4) sinh(x)

Before the summer solstice,  I'll commit my code to Maxima. Till then, find it at https://github.com/barton-willis/function_convert

--Barton

________________________________
From: Raymond Toy <[email protected]>
Sent: Saturday, May 2, 2026 9:44 PM
To: [email protected] <[email protected]>
Subject: Re: [Maxima-discuss] 'demoivre' not quite up to Wolfram's 'ExpToTrig' ?

Caution: Non-NU Email


On 5/2/26 6:05 PM, Henry Baker wrote:

I'm trying to 'undo' exponentialize on sinh(x), cosh(x), etc.

While demoivre(exp) works on sin(x), cos(x), it doesn't work on sinh(x), cosh(x).

But you can trick demoivre by substituting x=%i*y, do demoivre, and then substitute back y=x/%i.

Why isn't 'demoivre' smart enough to do this itself ?

This is what I used to do, but try out Barton’s excellent function_convert. You have to get it from https://github.com/barton-willis/function_convert<https://urldefense.com/v3/__https://github.com/barton-willis/function_convert__;!!PvXuogZ4sRB2p-tU!F_aaaaESnKDmCmOO4MJX1J9pzWOUhiEDoxG6xkGQjRb4jjFFYYynoh-Z73IrC7h0A_X34z_nAoXM4oveCTM$>. Then:


(%i17) exponentialize(sinh(x));

                                    x     - x
                                  %e  - %e
(%o17)                            ───────────
                                       2
(%i18) function_convert(exp=hyperbolic, %o17);
x = - x
        - x
x = - %e
      x     - x
x = %e  - %e
x = sinh(x)

(%o18)                              sinh(x)


Not sure why there’s extra output. Use list_converters() to see what conversions it can do.

_______________________________________________
Maxima-discuss mailing list
[email protected]<mailto:[email protected]>
https://lists.sourceforge.net/lists/listinfo/maxima-discuss<https://urldefense.com/v3/__https://lists.sourceforge.net/lists/listinfo/maxima-discuss__;!!PvXuogZ4sRB2p-tU!F_aaaaESnKDmCmOO4MJX1J9pzWOUhiEDoxG6xkGQjRb4jjFFYYynoh-Z73IrC7h0A_X34z_nAoXMNUX0K-g$>


&#8203;

_______________________________________________
Maxima-discuss mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/maxima-discuss