Changing order of integration/summation



On 9/1/08, John Pye <john.pye at anu.edu.au> wrote:

>  cp0(tau) := subst(%Tc/tau,T,sum(%a(i)*tau^i,i,0,n) +
>  sum(%b(i)*(%beta(i)/T)^2*exp(%beta(i)/T)/(exp(%beta(i)/T)-1)^2,i,0,m))
>
>  Now, I want to calculate the following:
>
>  -tau/R*integrate(1/tau^2*cp0(tau), tau) + 1/R*integrate(1/tau*cp0(tau),tau)
>
>  Problem is that when this evaluates, it keeps the integral signs, rather
>  than actually evaluating and expanding and simplifying.

Hmm, I thought maybe declare(integrate, linear); expand(<whatever>);
would do it, but that doesn't cause integrate to distribute over sum.
Can anyone think of a simple way to do it? I have some other ideas
about messier stuff.

best

Robert Dodier