I'd normally simulate it to find out. To solve the equation, approximate the integral using a spreadsheet such as excel, splitting up the integral into as many small angle segments as you want, or keep using more until the answer doesn't change much.

Bessel functions are available in excel if you activate the engineering toolkit.

Agreed with Malcolm White , apart from this you can also use some online calculators for verifying your results.

thank you very much for your help