Matlab doesn't do the complicated integration

I have tried to do a double integration using symbolic expression. However at somepoint the integration just stops. The output will be the same equation that I typed in (int(...)) instead of the actual answer of integration. Here are my codes:

syms xj yj

xije=0.0909090909090909;

yije=0.272727272727273;

xj1=0;yj1=0;

xj2=0.1818;yj2=0.1818;

f1=0.188+0.812/xj2^2*(2*xj2*xj-xj^2);

x=xije-xj;y=yije-yj;

x1=xije-xj1;x2=xije-xj2;

y1=yije-yj1;y2=yije-yj2;

R=sqrt(x^2+y^2);

f2=1/R^3;

f = f1*f2;

sigmaz=int(f,xj,x1,x2)

And heres the output:

Answer 1

[Walter Roberson]

int is for closed form integration to get an indefinitely precise solution. You cannot justify getting an indefinitely precise solution to an integration involving imprecise numbers such as 0.188.

It is a category error to use floating point numbers with int() or solve(). You should use vpaintegral() and vpasolve() instead.

Answer 2

[Ameer Hamza]

What about something like this

f = f1*f2;
sigmaz=int(f,xj)
I = subs(sigmaz, xj, x2) - subs(sigmaz, xj, x1)

It gives following expression in Live script