Question

(1/1-x)-(1/1+x)-(2x/1+x^2)-(4x^3/1+x^4)-(8x^7/1+x^8)

Answer 1

=(1+x-1+x)/(1-x)(1+x)-2x/(1+x^2)-4x^3/(1+x^4)-8x^7/(1+x^8)

=2x/(1-x^2)-2x/(1+x^2)-4x^3/(1+x^4)-8x^7/(1+x^8)

=2x/(1-x^2)-2x/(1+x^2)-4x^3/(1+x^4)-8x^7/(1+x^8)

=2x(1+x^2-1+x^2)/(1-x^2)(1+x^2)-4x^3/(1+x^4)-8x^7/(1+x^8)

=4x^3/(1-x^4)-4x^3/(1+x^4)-8x^7/(1+x^8)

以此类推

=16x^15/(1-x^16)