Warning: Explicit integral could not be found

Hi,

Appended below is my piece of code using which I was finding the integration of some function which is essentially a difference of 2 Q functions. I'm getting this warning: Explicit integral could not be found. But it is still showing a result. Is this result correct and can I use it inspite of the error? How do I fix this problem?

clear all;
close all;
clc;
syms R positive;
syms beta positive;
syms z real;
syms u;
syms k positive;
syms r positive;
syms T positive;
syms y;
syms v positive;
a=-(pi+(R*beta)/(r+2*R));
b=((R*beta)/(r+2*R))-pi;
f=exp(-(u*u/2));
q1=(1/sqrt(2*pi))*int(f,u,(sqrt(2*k))*(z-2*pi),inf);
q2=(1/sqrt(2*pi))*int(f,u,(sqrt(2*k))*z,inf);
q=q1-q2;
q_in=int(q,z,a,b);
new_in=int(q_in,r,(2*v*T*sin(y))-R,2*v*T*sin(y))

Answer 1

[Walter Roberson]

When an explicit integral cannot be found, and the bounds are numeric and there are no free variables other than the variable of integration, then MuPAD will do a numeric integration.

However, you have a number of free variables in your integrals, so numeric integration cannot be done.

When I test, I find that q_in is representable explicitly, but not new_in .

When an explicit integral cannot be found and a numeric integral cannot be done, an expression would still be returned: it would be an expression involving an unresolved integration.