若f(x-1)=x²-2x+3(x≤1),则f^-1(4)等于

若f(x-1)=x²-2x+3(x≤1),则f^-1(4)等于
若f(x-1)=x²-2x+3(x≤1),则f^-1(4)等于

若f(x-1)=x²-2x+3(x≤1),则f^-1(4)等于
令f(x-1)=x²-2x+3=4
x<=1
所以x=1-√2
则x-1=-√2
所以f(-√2)=4
所以
f^-1(4)=-√2