problem with integration of gaussian distribution

Thanks for your both help.

Maxima computes the integration.
The result may be right, but is to complicated to interpret.
Exponentialze doesnt seem to work for this solution.

I thought i could help maxima with some "wise" ;)
substitutions.
I found out that Maxima solves something like this as expected:
integrate(exp(-x^2-2*x),x,minf,inf);

What must I do, to let Maxima sort some summands in powers of p?
Is it possible to force Maxima to use a given substitution to make the terms 
easier?

Greets Robert


Am Montag, 6. Juli 2009 18:03:45 schrieb Leo Butler:
> On Mon, 6 Jul 2009, Robert Riemann wrote:
>
> < Hi all,
> <
> < i have problems to get Maxima solve an integral about a
> < bell-shaped curve with a weighting function phi.
> <
> < I tried it with the following code:
> <
> < assume( m > 0, d > 0, h > 0, A > 0)$
> < phi(p) := A*exp(-(p-p_0)^2/(h/d)^2);
> < psi(x,t) :=
> integrate(phi(p)*(2*%pi*h)^(-1)*exp(%i/h*(p*x-p^2/(2*m)*t)),p,minf,inf);
>
> Note that x does not appear in the rhs. Also, I think you want to write
>
> integrate(...)$
> psi(x,t) := ''%;
>
> This will compute the integral once.
>
> <
> < The result should be a bell-shaped curve to.
> <
> < What do i have to do to get a human-friendly solution (not with sin, cos,
> but exp) of this integral? < Is this possible with maxma/wxmaxima?
>
> Try:
> integrate(...)$
> %,exponentialize$
> psi(x,t) := ''%;
>
> The second line does what it says.
>
> Leo