Thanks for your question.
By "e", I assume you intend Euler's constant 2.718... Maxima uses %e to
represent that constant, and indeed
integrate(%e^(-x),x,1,5)
returns %e^-1-%e^-5 . You can get the numerical value of that with
float(...) or ..., numer.
But Maxima should actually be able to calculate integrate(a^(-x),x,1,5) with
the parameter x, which is of course 1/(a*log(a))-1/(a^5*log(a)). This seems
like a bug. It even fails on integrate(2^(-x),x,1,5) -- so it's not some
subtle question relating to the sign of a or whatever. After all, it is
perfectly happy to calculate the indefinite integral integrate(a^(-x),x)
=> -1/(a^x*log(a)) .
Sorry about that!
-s
On Wed, Feb 16, 2011 at 15:57, Chi Ben <xbenchi at gmail.com> wrote:
> Hi all,
> I guess this is a professional group working with Maxima, so my inquiry for
> basic knowledge of Maxima may not be very attractive for you to explore. But
> I will really appreciate your help.
> My question is:
> When I'm using the integrate function to evaluate an expression, sometimes
> Maxima gives me a value after calculation. But sometimes it just gives me a
> formal mathematical expression. For example, when I enter this:
> integrate(e^(-x),x,1,5);
> I get an expression with the integration symbol, the limits and everything,
> instead of the evaluation result.
> Can you please tell me how to get the numbers I'm looking for?
> Thanks,
> Chi Ben
>
>
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