Hi,

I meet a problem when I want to find the derivative of an integral with parameters when th eintegral has an option for numerical evaluatio.  For example

>  S := Int(sin(a*x)/x,x=0..infinity,method=_DEFAULT);

> diff(S,a);

Error, (in diff/Int) invalid Int(...) format

What is the correct syntax ?

Thanks, 

 Dan

How can I persuade Maple 16 to simplify such double sums to zero?  (The competition does it in a snap).

sum(sum( m[i]*m[j]*(x[i] - x[j]), i=1..N), j=1..N);

sum(sum( m[i]*m[j]*(x[i] - x[j])*(y[i] - y[j])*(z[i] - z[j]), i=1..N), j=1..N);

The sum elements are antisymmetric in the (i,j) indices so for every element there is another one cancelling it.