I=(1/2)(I1-I2) where I1=(x2+a2/x4+a4)dx=1+a2/x2/x2+a4/x2.Now write denominator as (x-a2/x)2+2a2 and put x-a2/x=t,It becomes dt/t2+2a2 which can be easily integrated.
Now,I2=(x2-a2/x4+a4)dx.Again divide nr and dr by x2 and write dr. as (x+a2/x)2-2a2.Now,Put t=x+a2/x,It becomes dt/t2-2a2 which is easy to integrate.
MAKING A MISTAKE IS HUMAN BUT REPEATING IT IS IDIOTIC.