Question

Please help - Let f(x)=x−1/x+1.

Answer 1

`\\ \sf\longmapsto f(x)=(x-1)/(x+1)`

`\\ \sf\longmapsto f^(-1)(x)=(1)/(f(x))=dfrac{x+1}{x-1}`

Now

`\\ \sf\longmapsto f^(-1)(3)=(3+1)/(3-1)=4/2=2`

And

`\\ \sf\longmapsto (f^(-1))'(3)=f(3)=(3-1)/(3+1)=2/4=1/2`

Done