Given [tex]\( f(x) = \frac{2}{3} x^2 - 6 \)[/tex], answer the following questions. Show your work.

a. Find [tex]\( f^{-1}(x) \)[/tex].



Answer :

Sure, let's find the inverse of the function [tex]\( f(x) = \frac{2}{3}x^2 - 6 \)[/tex].

1. Set the function equal to [tex]\(y\)[/tex]:
[tex]\[ y = \frac{2}{3} x^2 - 6 \][/tex]

2. Solve for [tex]\(x\)[/tex] in terms of [tex]\(y\)[/tex]:
[tex]\[ y + 6 = \frac{2}{3} x^2 \][/tex]

3. Multiply both sides by [tex]\(\frac{3}{2}\)[/tex] to isolate [tex]\(x^2\)[/tex]:
[tex]\[ \frac{3}{2}(y + 6) = x^2 \][/tex]
[tex]\[ x^2 = \frac{3}{2}(y + 6) \][/tex]

4. Take the square root of both sides to solve for [tex]\(x\)[/tex]:
[tex]\[ x = \pm \sqrt{\frac{3}{2}(y + 6)} \][/tex]

5. Simplify the expression inside the square root:
[tex]\[ x = \pm \sqrt{\frac{3}{2}y + \frac{3}{2} \cdot 6} \][/tex]
[tex]\[ x = \pm \sqrt{\frac{3}{2}y + 9} \][/tex]

6. Rewrite as separate positive and negative solutions:
[tex]\[ x = 3 \sqrt{0.166666666666667y + 1} \][/tex]
[tex]\[ x = -3 \sqrt{0.166666666666667y + 1} \][/tex]

So, the inverse function [tex]\( f^{-1}(y) \)[/tex] is given by:
[tex]\[ f^{-1}(y) = 3 \sqrt{0.166666666666667y + 1} \][/tex]
or
[tex]\[ f^{-1}(y) = -3 \sqrt{0.166666666666667y + 1} \][/tex]

Thus, the inverse function [tex]\( f^{-1}(x) \)[/tex] can be written as:

[tex]\[ f^{-1}(x) = 3 \sqrt{0.166666666666667x + 1} \][/tex]
or
[tex]\[ f^{-1}(x) = -3 \sqrt{0.166666666666667x + 1} \][/tex]