MATLAB: Integrate definite integrals matlab

Question

Hi

What is wrong with the following code please?

thanks

 int((5*x)/((x^3-(7*x))^4), x=-1..1)

Answer 1

>> syms x
>> int((5*x)/((x^3-(7*x))^4),-1,1)
ans =
NaN

Which is correct if you consider you are working with a non-convergent improper integral