Hi,

On Tue, Aug 18, 2009 at 8:42 PM, rjf<fate...@gmail.com> wrote:
>
> did you mean to integrate with respect to "x^2" ?

Yes.

> Well, x^2 doesn't occur in   f(x).  So let's rename x^2 as y.
> What is the integral of f(x) with respect to y?
>
> It is y*f(x).
>
> substituting back x^2 for y,  you get x^2*f(x).

Are you saying during integration maxima is not aware
that "x^2" is the square of "x"?

Take following examples:
----------
(%i4) integrate(log(x), x);
(%o4)                            x log(x) - x

(%i5) integrate(log(x^2), x^2);
                                     2
(%o5)                             2 x  log(x)
----------

"log" is certainly aware of it.

> Certainly Maxima expects "the variable of integration" as
> the second argument.  Anything else is asking for trouble.

Then maxima should throw error instead of giving a wrong
answer silently. This is rather bizarre given maxima is known
to be over-cautious during integration and sometime
it asks too many questions, even something like
--------
(%i6) integrate(1/x, x, 0, 1);
Is  x + 1  positive, negative, or zero?
--------

Cheers,
Golam

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