Subject: [1] enter (in console) ; [2] implicit functions
From: Robert Dodier
Date: Fri, 28 Sep 2012 15:44:00 +0000 (UTC)
On 2012-09-28, ivo welch <ivo.welch at gmail.com> wrote:
> 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. again nothing.
> a ^c gets me a console interrupt.
Console input can span multiple lines, and is terminated by dollar sign
or semicolon. Dollar sign => don't display result, semicolon => display
result.
Also, equations are indicated by '=' instead of '=='. In general, '='
represents identity (same expression) and 'equal' represents equivalence
(equal values). Be that as it may, equations are indicated by '='.
So in your example,
solve (y + 2 = 0, y);
=> [y = - 2]
(solve returns a list of solutions; in this case there is just one.)
> [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])
Well, Maxima can't solve y + log(y) + x = 0 (its solver is not too
strong, sorry about that). But you can make an implicit plot.
load (implicit_plot);
implicit_plot (y + log(y) + x = 0, [x, -10, 10], [y, -10, 10]);
Perhaps contour_plot is also useful in this context.
> (I also want to use M to ascertain whether dy/dx > 0 .)
Sorry, I don't know how.
> help for a poor beginner is appreciated.
Welcome to Maxima. Good luck & have fun.
Sounds like you have some experience with mathematics and Mathematica. I
am interested in your opinions. If stuff doesn't work for you, let us
know. I can't guarantee any timely response, but I think it is a good
idea to keep the discussion going.
Robert Dodier