令y=(x-1),则f(y) = 3- x^2,因x = y+1 ,则f(y)= 3-(y+1)^2
y=(x+1) 代入f(y),有f(x+1) = 3 - ((x+1)+1)^ 2= 3 -(x+2)^2 = 3-x^2-4x-4 = -x^2-4x-1
令y=(x-1),则f(y) = 3- x^2,因x = y+1 ,则f(y)= 3-(y+1)^2
y=(x+1) 代入f(y),有f(x+1) = 3 - ((x+1)+1)^ 2= 3 -(x+2)^2 = 3-x^2-4x-4 = -x^2-4x-1