# [Maxima] technical question on Maxima

Jerome Huck jeromehuck at orange.fr
Thu Jun 28 14:15:48 CDT 2012

```>From Jerome Huck

Good morning.
I do not know if you are the right people but I have a technical
question/idea relative to Maxima.
Can you forward my mail to them ?

Best regards.

Good morning.
I was trying to solve some complicated 3D flow with approximations using
Maxima.
I need to solve a 2nd order diff equation, the one on attached hardcopy
HC. Instead of having having exp in the output, I would like to have
hyperbolic sinh/cosh functions. I did the same problem with changing the
plus into a minus for the zero order term and the solution is clean with
Maxima, even with the boundary conditions, see HC1.

I downloaded the source code of Maxima to try to find an explanation. I
have a good knowledge of SCHEME language which is a derivative of  LISP.
I found the ODE2/MAC and ODE2.USG and try to understand them.

In Maxima, in CC2, in this ODE2 source code you have the EXPONENTIALIZE
to control the kind of output, a sin/cos solution or classical exp
function. (as the control flag in MAXIMA)

if exponentialize = false then
return(y = %e^(-%f%*x/2) * (%k1*sin(alpha) + %k2*cos(alpha))),
return(y = %e^(-%f%*x/2) * (%k1*exp(%i*alpha) + %k2*exp(-%i*alpha))))

Why  do we not have an HYPERBOLIZE to control the output of CC2,
SINH/COSH or exp, a few lignes above in CC2?
It could be a good idea to improve the solution. With my problem, when I
put my boundary conditions, I ended with a very complicated
expression...and I further need this solution to improve this output for
my complex 3D flow.

What do you think, a good idea for a further release of MAXIMA?

Best regards.

Jerome Huck.

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