I.
Given a function f with domain D and range R, and the inverse function
![f ^{-1}](https://tex.z-dn.net/?f=f%20%5E%7B-1%7D%20)
,
then the domain of
![f ^{-1}](https://tex.z-dn.net/?f=f%20%5E%7B-1%7D%20)
is the range of f, and the range of
![f ^{-1}](https://tex.z-dn.net/?f=f%20%5E%7B-1%7D%20)
is the domain of f.
II. We are given the function
![f(x)= \sqrt{x-5}](https://tex.z-dn.net/?f=f%28x%29%3D%20%5Csqrt%7Bx-5%7D%20)
,
the domain of f, is the set of all x for which
![\sqrt{x-5}](https://tex.z-dn.net/?f=%5Csqrt%7Bx-5%7D%20)
makes sense, so x is any x for which x-5
![\geq](https://tex.z-dn.net/?f=%20%5Cgeq%20)
0, that is x≥5.
the range is the set of all values that f can take. Since f is a radical function, it never produces negative values, in fact in can produce any value ≥0
Thus the Domain of f is [5, ∞) and the Range is [0, ∞)
then , the Domain of
![f ^{-1}](https://tex.z-dn.net/?f=f%20%5E%7B-1%7D%20)
is [0, ∞) and the Range of
![f ^{-1}](https://tex.z-dn.net/?f=f%20%5E%7B-1%7D%20)
is [5, ∞)
III.
Consider
![f(x)= \sqrt{x-5}](https://tex.z-dn.net/?f=f%28x%29%3D%20%5Csqrt%7Bx-5%7D%20)
to find the inverse function
![f^{-1}](https://tex.z-dn.net/?f=f%5E%7B-1%7D%20)
,
1. write f(x) as y:
![y= \sqrt{x-5}](https://tex.z-dn.net/?f=y%3D%20%5Csqrt%7Bx-5%7D%20)
2. write x in terms of y:
![y= \sqrt{x-5}](https://tex.z-dn.net/?f=y%3D%20%5Csqrt%7Bx-5%7D)
take the square of both sides
![y^{2} =x-5](https://tex.z-dn.net/?f=y%5E%7B2%7D%20%3Dx-5)
add 5 to both sides
![y^{2} +5=x](https://tex.z-dn.net/?f=y%5E%7B2%7D%20%2B5%3Dx)
![x=y^{2} +5](https://tex.z-dn.net/?f=x%3Dy%5E%7B2%7D%20%2B5)
3. substitute y with x, and x with
![f^{-1}(x)](https://tex.z-dn.net/?f=f%5E%7B-1%7D%28x%29%20)
:
![f^{-1}(x)=x^{2} +5](https://tex.z-dn.net/?f=f%5E%7B-1%7D%28x%29%3Dx%5E%7B2%7D%20%2B5)
These steps can be applied any time we want to find the inverse function.
IV. Answer:
![f^{-1}(x)=x^{2} +5](https://tex.z-dn.net/?f=f%5E%7B-1%7D%28x%29%3Dx%5E%7B2%7D%20%2B5)
, x≥0
y≥0, where y are all the values that
![f^{-1}](https://tex.z-dn.net/?f=f%5E%7B-1%7D)
can take
Remark: the closest choice is B