Questions: Let f(x)=sqrt(2x-1)-3. Its inverse will have a domain of [-3, infinity). Which of the following represents f^(-1)(x) ?
Select the correct answer below:
f^(-1)(x)=(2x-1)^2+3
f^(-1)(x)=1/3(2x-1)^2
f^(-1)(x)=2(x+3)^2-1
f^(-1)(x)=1/2[(x+3)^2+1]
Transcript text: Let $f(x)=\sqrt{2 x-1}-3$. Its inverse will have a domain of $[-3, \infty)$. Which of the following represents $f^{-1}(x)$ ?
Select the correct answer below:
$f^{-1}(x)=(2 x-1)^{2}+3$
$f^{-1}(x)=\frac{1}{3}(2 x-1)^{2}$
$f^{-1}(x)=2(x+3)^{2}-1$
$f^{-1}(x)=\frac{1}{2}\left[(x+3)^{2}+1\right]$
Solution
Solution Steps
Step 1: Define the Function
The original function is given by
\[
f(x) = \sqrt{2x - 1} - 3
\]
Step 2: Swap Variables
To find the inverse function, we swap \(x\) and \(y\):
\[
x = \sqrt{2y - 1} - 3
\]
Step 3: Isolate the Square Root
Next, we isolate the square root by adding 3 to both sides:
\[
x + 3 = \sqrt{2y - 1}
\]
Step 4: Square Both Sides
Now, we square both sides to eliminate the square root:
\[
(x + 3)^2 = 2y - 1
\]
Step 5: Solve for \(y\)
We then solve for \(y\) by adding 1 to both sides and dividing by 2: