已知函数f(x+1)=x2-2x,则f(x-1)的解析式为解:设t=x+1==>x=t-1∴f(t)=t^2-2t+1-2t+2= t^2-4t+3f(x)=x^2-4x+3f(x-1)= (x-1)^2-4(x-1)+3=x^2-2x+1-4x+4+3= x^2-6x+8
f(x+1)=x^2-2x =(x+1)^2-4(x+1)+3所以 f(x)=x^2-4x+3所以 f(x-1)=(x-1)^2-4(x-1)+3 =x^2-6x+8