# [Maxima] strange behaviour with simple decimals

Andrey G. Grozin A.G.Grozin at inp.nsk.su
Tue Apr 17 10:05:58 CDT 2007

```I'd like to stress one general point about maxima (or any other CAS).
maxima *always* transforms its input to its internal representation. It is
*not* a passive "paper" on which you can write some expression and expect
it to stay in the form you have written. This is in no way restricted to
numbers.

(%i1) a:x-y\$
(%i2) part(a,0); part(a,2); part(a,2,0);
(%o2)                                  +
(%o3)                                 - y
(%o4)                                  -

This shows that when you write x-y, maxima immediately transforms this to
its internal representation x+(-y).

(%i5) a:x^(1/2);
(%o5)                               sqrt(x)
(%i6) part(a,0);
(%o6)                                sqrt

The power 1/2 is transformed to sqrt.

And so on. Such examples are innumerable. So, the expectation that maxima
(or any other CAS) will work with the expression you input is wrong. It
will always transform it into its internal representation, and work with
it.

Andrey
```