设函数f {(1-x)/(1+x)}= x,则f(x)表达式为A (1+x)/(1-x) B (1+x)/(x-1) C (1-x)/(1+x)D 2x/(x+1)

设函数f {(1-x)/(1+x)}= x,则f(x)表达式为A (1+x)/(1-x) B (1+x)/(x-1) C (1-x)/(1+x)D 2x/(x+1)
设函数f {(1-x)/(1+x)}= x,则f(x)表达式为
A (1+x)/(1-x)
B (1+x)/(x-1)
C (1-x)/(1+x)
D 2x/(x+1)

设函数f {(1-x)/(1+x)}= x,则f(x)表达式为A (1+x)/(1-x) B (1+x)/(x-1) C (1-x)/(1+x)D 2x/(x+1)
令a=(1-x)/(1+x)
1+a=1+(1-x)/(1+x)=2/(1+x)
1+x=2/(1+a)
x=2/(1+a)-1=(1-a)/(1+a)
则f(a)=(1-a)/(1+a)
所以f(x0=(1-x)/(1+x)
选C

设(1-x)/(1+x)=y,可以求出x=(1-y)/(1+y),这就是关于x的函数，所以f(x)=(1-x)/(1+x),答案为c