Question

函数,1.求f(x)=x-1/x+1的值域2.已知一次函数f(x)满足f [f(x)]=9x/4+5,则f(x)=3.设

Answer 1

1.求f(x)=x-1/x+1的反函数

f(y)=y+1/1-y

f(y)的定义域是

y≠1

所以f(x)=x-1/x+1的值域就是f(x)≠1

3.f(1/2)即g(x)=1/2

1-2x=1/2

x=1/4

f(1/2)=1-x^2/x^2

=1-(1/4)^2/(1/4)^2

=1-1

=0