error in the integration of complex functions (FW10077)

[parisse]

If f is entered as an algebraic function, you get the exact answer

Code:

f(x,n):=sum(cos(k*x),k,1,n);
int(f(x,ceil(x)),x,0,2);

returns 4*tan(1)/(tan(1)^4+2*tan(1)^2+1)+2*tan(1/2)/(tan(1/2)^2+1)-4*tan(1/2)/(tan(1/2)^4+2*tan(1/2)^2+1)
If f is entered as a program

Code:

f(x,n):= begin local j,y; y:=0; for j from 1 to n do y:=y+cos(j*x); end; end;

then f(x,ceiling(x)) returns an error in Xcas while returning 0.0 on the Prime. I guess it's again because an exception is not raised on the Prime. This explains why you get 0 for the integral.