f(x)=(x^n+x^(n-1)-x^(n-1)-x^(n-2)+x^(n-2)+x^(n-3)-...+(-1)^(n-1)*x+(-1)^(n-1)-(-1)^(n-1))/(x+1)=x^(n-1)-x^(n-2)+x^(n-3)-...+(-1)^(n-1)+(-1)^n/(x+1)所以f^(n)(x)=[(-1)^n/(x+1)]^(n)=(-1)^n*(-1)^n*n!/(x+1)^(n+1)=n!/(x+1)^(n+1)