# [Maxima] plot numerical question

Kostas Oikonomou ko at research.att.com
Wed Mar 11 15:36:37 CDT 2009

```Thanks to all for the replies.  I like Andrej's solution most.
But why doesn't it work if I say

plot2d(r4(s), [s,200,300])?

"r4" instead of "r4(s)" is confusing.

Kostas

Andrej Vodopivec wrote:
> Use bfloats:
>
> r4(s) := block([s:bfloat(s)], s!/(((s/4)!)^4 * 4^s));
> plot2d(r4, [s,200,300]);
>
> Andrej
>
> On Wed, Mar 11, 2009 at 8:36 PM, Kostas Oikonomou <ko at research.att.com> wrote:
>> I have a function
>>
>> r4(s) := s!/(((s/4)!)^4 * 4^s)
>>
>> and I am trying to plot it over the range [200,300]:
>>
>> plot2d(r4(s), [s,200,300])
>>
>> plot2d returns silently, i.e. it produces nothing. � I am
>> fairly sure the problem is that the computation involves
>> intermediate numbers that are too large, although the final
>> result is well within the rang of an ordinary float. �E.g.
>> r4(300) is of the order of 10^-4.
>>
>> I thought I had seen a solution to this kind of problem with
>> plot somewhere on the list, but I can't find it. � It seems
>> to me the answer would be worth adding to the documentation
>> for plotting.
>>
>> (This is Maxima 5.17.1 using SBCL, same with CMUCL)
>>
>> � � � � � � � � � � � � � � � � � � � � � � � �Kostas
>

```