simple derivative function question



On Wed, Jan 17, 2007 at 10:53:33AM -0500, sen1 at math.msu.edu wrote:
> Thanks to all who responded with tips on how to define derivative
> functions.
> 
> Some more questions:
> 
> 1. What does maxima actually do with the next definition?
> 
>    (A)   f(x):= diff(f(x),x)

maxima creates a "noun form" for the derivative.. Because maxima
doesn't know what f(x) means, it simply echos back the fact that you
mean "the derivative of f(x)" as a symbolic construct, namely
'diff(f(x),x).

When defining a function, the right hand side of the := operator is
automatically quoted as far as I can tell.

Noun forms are symbolic representations of a thing which could in
principle be computed if more information were known.

'diff(x^2,x) => noun form (due to quotes)
diff(x^2,x) => 2*x (evaluated by the top level read-eval-print loop)

-- 
Daniel Lakeland
dlakelan at street-artists.org
http://www.street-artists.org/~dlakelan