beginner questions: return on Maxima console and working with implicit functions

thanks, volker, stavros, and andrew.  this was very helpful.

I would put a notice about the required '$' or ';' lineend somewhere
in a prominent popup or startup line the first few times that Maxima
is invoked.  This has probably let many "silent" users to give up
prematurely over the years.

I am definitely warming up to Maxima over Mathematica.

I like the "rational" assumption in Maxima, as well as its more
central assume feature.  Maxima seems faster, too.  Its default
wxMaxima notation output seems nicer.

Mathematica seems to have a more sophisticated FullSimplify
simplification routine---in fact, I wonder whether Maxima there is not
a heuristic simplification that has some IQ and tries all sorts of
different approaches by itself without me having to know what packages
I could try.

Mathematica puts its graphs into its notebook, while wxMaxima put them
into external gnuplot windows.  I believe wxplot can embed plots, but
when I want to use other plots, such as implicit plots, I probably
lose this.  I wish wxMaxima had a configure choice to integrate all
graphs.

Mathematica has one big advantage, which is books.  I would purchase a
150 page book that is a reasonable beginner's guide.  fortunately,
Mathematica's drawback is that its books are 2,000 pages.  I usually
just read the first few chapters.

one thing about Maxima that cannot be changed: is that the name of the
package is too generic.  google searches lead to all sorts of
irrelevant results.  I now know a lot more about Nissan maximas.

in any case, Maxima is an impressive package.

Cheers.

/iaw




On Fri, Sep 28, 2012 at 3:12 AM, Volker van Nek <volkervannek at gmail.com> wrote:
>
> 2012/9/28 ivo welch <ivo.welch at anderson.ucla.edu>
>>
>> dear maxima experts---
>>
>> [1] I am trying to switch from Mathematica to Maxima.  I downloaded
>> and installed it on ubuntu linux 12.04.1 .    I can use wxMaxima
>> successfully.  I would like to use the basic command line interface.
>> I type $ maxima, and then "solve( y + 2 == 0, y)" to the (%i1) prompt
>> and hit enter...and nothing happens.  then I try shift-enter.  a ^c
>> gets me a console interrupt.
>
>
> Maxima needs a terminator at the end of an expression. Use ; to view the
> answer and $ if the answer should not be displayd.
>
> wxMaxima automatically adds a semicolon.
>
> The operator for an equation is simply =
>
>>
>> [2] I am trying to work with implicit functions.  an illustration of
>> what I want to accomplish is
>>
>> eqn : solve( y + log(y) + x = 0, y)
>> plot(eqn, [x,0,1])
>
>
>  To answer this I need to load an additional package:
>
> (%i2) eqn : y + log(y) + x = 0$
>
> (%i3) load(implicit_plot);
>
> (%o3) "/usr/local/share/maxima/5.28.0/share/contrib/implicit_plot.lisp"
> (%i4) implicit_plot(eqn, [x,0,1], [y,0,1])$
>
>
> solve cannot solve eqn. So I load another package:
>
> (%i5) load(to_poly_solve);
>
> Loading maxima-grobner $Revision: 1.6 $ $Date: 2009-06-02 07:49:49 $
> (%o5) "/usr/local/share/maxima/5.28.0/share/to_poly_solve/to_poly_solve.mac"
> (%i6) to_poly_solve(eqn, y);
>
> (%o6) %union([y = lambert_w(%e^-x)])
> (%i7) plot2d(lambert_w(%e^-x), [x,0,1])$
>
> To compute dy/dx I type
>
> (%i8) diff(lambert_w(%e^-x), x);
>
> (%o8) -%e^(-lambert_w(%e^-x)-x)/(lambert_w(%e^-x)+1)
>
> I don't know much about Lambert's W function. So I can't help with dy/dx >
> 0.
>
> I hope someone else can answer here.
>
> Volker van Nek
>
>>
>> I know this is wrong...but how would I do this correctly?  (I also
>> want to use M to ascertain whether dy/dx > 0 .)
>>
>> help for a poor beginner is appreciated.
>>
>> /iaw
>>
>>
>> ----
>> Ivo Welch (ivo.welch at gmail.com)
>> http://www.ivo-welch.info/
>> J. Fred Weston Professor of Finance
>> Anderson School at UCLA, C519
>> Editor, Critical Finance Review, http://www.critical-finance-review.org/
>> _______________________________________________
>> Maxima mailing list
>> Maxima at math.utexas.edu
>> http://www.math.utexas.edu/mailman/listinfo/maxima
>
>