Find the inverse of the function: [tex]y = 2x^2 - 4[/tex]

A. [tex]y = \pm \sqrt{x} + 2[/tex]
B. [tex]y = \pm \sqrt{\frac{x+4}{2}}[/tex]
C. [tex]y = \pm \frac{\sqrt{x+4}}{2}[/tex]
D. [tex]y = \pm \sqrt{x} - 2[/tex]



Answer :

To find the inverse of the function [tex]\( y = 2x^2 - 4 \)[/tex], we need to express [tex]\( x \)[/tex] in terms of [tex]\( y \)[/tex].

1. Start with the given function:
[tex]\[ y = 2x^2 - 4 \][/tex]

2. Solve for [tex]\( x \)[/tex]:
[tex]\[ y + 4 = 2x^2 \][/tex]

3. Isolate [tex]\( x^2 \)[/tex]:
[tex]\[ x^2 = \frac{y + 4}{2} \][/tex]

4. Take the square root of both sides: Note that taking the square root introduces both the positive and negative roots.
[tex]\[ x = \pm \sqrt{\frac{y + 4}{2}} \][/tex]

Therefore, the inverse functions are:
[tex]\[ x = \sqrt{\frac{y + 4}{2}} \quad \text{and} \quad x = -\sqrt{\frac{y + 4}{2}} \][/tex]

In other words, the inverse of the function [tex]\( y = 2x^2 - 4 \)[/tex] is:
[tex]\[ y = \pm \sqrt{\frac{x + 4}{2}} \][/tex]

Hence, the correct choice from the given options is:
[tex]\[ y = \pm \sqrt{\frac{x+4}{2}} \][/tex]