已知f(x+1)=x^2+1令t=x+1则x=t-1所以，f(t)=(t-1)^2+1=t^2-2t+2所以，f(x)=x^2-2x+2希望采纳~~~
f(x+1)=[(x+1)-1]²+1∴f(x)=(x-1)²+1=x²-2x+2
