https://s0.wp.com/latex.php?latex=%5Cdisplaystyle+%5Cint_0%5E%7B%5Cinfty%7D+%5Cfrac%7Bx%5E2%7D%7Bx%5E2+%2B+%28x%5E2+-+a%29%5E2%7D%5C+dx+%3D+%5Cint_0%5E%7B%5Cinfty%7D+%5Cfrac%7B1%7D%7B1+%2B+%5Cleft%28x+-+a%2Fx%5Cright%29%5E2%7D%5C+dx+%3D+%5Cfrac%7B%5Cpi%7D%7B2%7D%2C+%5Cquad+%5Ctext%7BRe%7D%28a%29+%3E+0.&bg=ffffff&fg=000000&s=0&c=20201002