观察系数,联想到二项式定理,可得
f(x)=x^5-5x^4+10x^3-10x^2+5x+1=(x^5-5x^4+10x^3-10x^2+5x-1)+2=(x-1)^5+2
易得反函数f-1(x)=(x-2)^(1/5)+1