Find a fraction 1/(1-x)-1/(1+x)-2x/(1+x^2)+(-4x^3)/(1+x^4) Seek process! Urgent, online, etc

Find a fraction 1/(1-x)-1/(1+x)-2x/(1+x^2)+(-4x^3)/(1+x^4) Seek process! Urgent, online, etc

It is mainly (1-x) (1 + x) = 1-x ^ 2 (1-x ^ 2) (1 + x ^ 2) = 1-x ^ 4 (1-x ^ 4) (1 + x ^ 4) = 1-x ^ 8 to solve the denominator