f(x)=(x-2)/(x+2),f(x-2/x+2)=-x/2,求f(x).
热心网友
f(x)=(x-2)/(x+2)，f((x-2)/)x+2)) = -x/2，求x. 解:设s = (x - 2)/(x + 2),则 x - 2 = s(x + 2)，即 x = 2(1 + s)/(1 - s)那么f(s) = f((x - 2)/(x + 2)) = -x/2 = (-1/2)×2×(1 + s)/(1 - s) = (s + 1)/(s - 1)所以 (s + 1)/(s - 1) = (x - 2)/(x + 2)即 [(x - 2)/(x + 2) + 1]/[(x - 2)/(x + 2) - 1] = (x - 2)/(x + 2)整理后得:x^2 + 4x - 4 = 0所以 x1 = -2 + √2，x2 = -2 - √2
热心网友
2楼对的
热心网友
既然已知f(x)=(x-2)/(x+2)，怎么还要求f(x)？