result = int(besselj(nu, x), x, 0, 4*sym(pi))
result =
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1713121/image.png)
Bessel J is a family of functions, distinguished by the ν value. You cannot get much of a result unless you specify the ν value you want to work with.
result0 = int(besselj(0, x), x, 0, 4*sym(pi))
result0 =
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1713126/image.png)
vpa(result0)
ans = 0.8340841018533418306979596564232