@tomleslie 

that is the problem that I want to solve, how can I change/ is there any changes I can do so that the second procedure is calling it, or is it impossible? (the argument to call it with is the problem

@tomleslie 
thank you, I knew that, but my problem is specific for that procedure I wrote :(

how to put my first procedure in the second?

@tomleslie 

thank you, I knew that, but my problem is specific for that procedure I wrote :(

@Kitonum 
yes, I m using an old cheep version for a poor student ;-)
that s great, thanks

@Kitonum 

Hi again, the code you wrote makes sence but somehow it is not working by me,
i got  the error :
Error, (in Simp38) wrong number (or type) of parameters in function add
I think the underlined (3) is the problem, but I can't find another mapple command than add that takes 3 parts.
3*h/8*(f(x0)+f(xn)+3*add(f(x(i)),i=1..n-1,3)+3*add(f(x(i)),i=2..n-1,3)+2*add(f(x(i)),i=3..n-1,3));

@Rouben Rostamian  

ohh yes. thanks very much ;-)

@Kitonum 
thanks very much ;-)