Select the correct answer.

Which function is the inverse of [tex]f(x)=\frac{\sqrt{x-2}}{6}[/tex]?

A. [tex]f^{-1}(x)=36 x^2+2[/tex], for [tex]x \geq 0[/tex]

B. [tex]f^{-1}(x)=6 x^2+2[/tex], for [tex]x \geq 0[/tex]

C. [tex]f^{-1}(x)=36 x+2[/tex], for [tex]x \geq 0[/tex]

D. [tex]f^{-1}(x)=6 x^2-2[/tex], for [tex]x \geq 0[/tex]



Answer :

To find the inverse of the function [tex]\( f(x) = \frac{\sqrt{x-2}}{6} \)[/tex], we follow a step-by-step process:

1. First, express [tex]\( y \)[/tex] in terms of [tex]\( x \)[/tex]:
[tex]\[ y = \frac{\sqrt{x-2}}{6} \][/tex]

2. Switch [tex]\( x \)[/tex] and [tex]\( y \)[/tex] to begin finding the inverse:
[tex]\[ x = \frac{\sqrt{y-2}}{6} \][/tex]

3. Clear the fraction by multiplying both sides by 6:
[tex]\[ 6x = \sqrt{y-2} \][/tex]

4. Square both sides to eliminate the square root:
[tex]\[ (6x)^2 = y - 2 \][/tex]
[tex]\[ 36x^2 = y - 2 \][/tex]

5. Solve for [tex]\( y \)[/tex] by adding 2 to both sides:
[tex]\[ y = 36x^2 + 2 \][/tex]

Thus, the inverse function is:

[tex]\[ f^{-1}(x) = 36x^2 + 2 \][/tex]

Among the given choices:
A. [tex]\( f^{-1}(x) = 36 x^2 + 2 \)[/tex], for [tex]\( x \geq 0 \)[/tex]
B. [tex]\( f^{-1}(x) = 6 x^2 + 2 \)[/tex], for [tex]\( x \geq 0 \)[/tex]
C. [tex]\( f^{-1}(x) = 36 x + 2 \)[/tex], for [tex]\( x \geq 0 \)[/tex]
D. [tex]\( f^{-1}(x) = 6 x^2 - 2 \)[/tex], for [tex]\( x \geq 0 \)[/tex]

The correct answer matches our derived inverse function. Therefore, the correct answer is:

A. [tex]\( f^{-1}(x) = 36 x^2 + 2 \)[/tex], for [tex]\( x \geq 0 \)[/tex].

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