You can often do this:
fun(x):=''f
fun(4)
instead of subst(x=4,f)
Maybe that will solve your problem.
It is possible to set derivabbrev:true
to change the output of derivatives to look like subscripts.
If you wish, you might be able to use
df[n]:= diff(f,x,n)
and then a DE might look like df[2]-a*f=0
RJF
Wolfgang Lindner wrote:
>"Stavros Macrakis" <macrakis at alum.mit.edu> schrieb:
>On 4/15/07, Wolfgang Lindner <LindnerW at t-online.de> wrote:
>
>
>>>(%i1) f(x):=exp(x)-1/4*x*exp(x);
>>>(%i2) solve(f(x)=0,x);
>>>(%o2) [x=4,%e^x=0]
>>>(%i3) diff(f(x),x) ; /* f prime */ ...
>>>AFAIK it is not possible to abbrevitae diff(f(x),x) with f'(x).
>>>I use fp(x) to name 'f prime' etc.
>>>Is there any symbol left (backquote?) to name f'(x) and causing no problems later?
>>>What is your recommended work around?
>>>
>>>
>
>
>
>>As a general rule, Maxima does a much better job with mathematical *expressions* than
>>with mathematical *functions* with names (like f).
>>So the natural way to handle this sort of thing in Maxima is
>>f: exp(x)-1/4*x*exp(x);
>>solve(f,x)$
>>solve(diff(f,x),x)
>>etc.>>
>>
>>
>
>Thank you for your interesting hints on Maxima's capabilities. In Germany we have a
>'didactical tradition in math' to perfer *functions* (at least since Felix Klein), not
>terms - but using CAS the situation seems be on other one.
>Following your advice will there be an 'uncomfortable term evaluation'?
>My students will (fequently) have to calculate function values, function tables etc.
>So - as far as I know - I should have to write
>
>(%i4) subst(x=4, f) /* instead of f(4) */
>
>if f is an term. Or is there an better possibility?
>If there would be an 'term evaluator' like
>
>(%i4') f | x=4 /* term f evaluated for x =4 */
>
>one would have a simpler and shorter 'functionlike' notation.
>
>So I have to decide: function - maybe no good job
> term - no usual evaluation a la f(x)
>
>
>HTH
>Wolfgang
>Leichlingen/Germany
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