1/x-1+1/x+1+2x/x²+1+4x³/x^4+1=(x+1+x-1)/(x-1)(x+1)+2x/(x²+1)+4x³/(x^4+1)=2x/(x²-1)+2x/(x²+1)+4x³/(x^4+1)=[2x(x²+1)+2x(x²-1)]/(x²-1)(x²+1)+4x³...