Select the correct answer.

If the graph of [tex]f(x) = 3^x[/tex] is reflected over the [tex]x[/tex]-axis, what is the equation of the new graph?

A. [tex]g(x) = -\left(\frac{1}{3}\right)^x[/tex]

B. [tex]g(x) = -(3)^x[/tex]

C. [tex]g(x) = \left(\frac{1}{3}\right)^x[/tex]

D. [tex]g(x) = 3^{-x}[/tex]



Answer :

To solve this problem, we need to understand the effect of reflecting a function over the [tex]\( x \)[/tex]-axis. Specifically, we start with the function [tex]\( f(x) = 3^x \)[/tex] and determine its new form after reflection.

### Step-by-Step Solution:

1. Original Function: The original function given is [tex]\( f(x) = 3^x \)[/tex].

2. Reflection Over the [tex]\( x \)[/tex]-Axis:
- Reflecting a function [tex]\( f(x) \)[/tex] over the [tex]\( x \)[/tex]-axis involves multiplying the function by [tex]\(-1\)[/tex].
- Mathematically, if [tex]\( f(x) \)[/tex] is the original function, the reflected function [tex]\( g(x) \)[/tex] is given by:
[tex]\[ g(x) = -f(x) \][/tex]

3. Apply Reflection to the Given Function:
- Since [tex]\( f(x) = 3^x \)[/tex], multiply it by [tex]\(-1\)[/tex] to get the new function:
[tex]\[ g(x) = -3^x \][/tex]

4. Match with Given Options:
- We now compare the derived equation [tex]\( g(x) = -3^x \)[/tex] with the provided options:
[tex]\[ \begin{aligned} \text{A. } & g(x) = -\left(\frac{1}{3}\right)^x \\ \text{B. } & g(x) = -(3)^x \\ \text{C. } & g(x) = \left(\frac{1}{3}\right)^x \\ \text{D. } & g(x) = 3^{-x} \end{aligned} \][/tex]

- Clearly, option B, [tex]\( g(x) = -(3)^x \)[/tex], matches our derived equation [tex]\( g(x) = -3^x \)[/tex].

5. Conclusion:
- The correct answer is B.

Therefore, if the graph of [tex]\( f(x)=3^x \)[/tex] is reflected over the [tex]\( x \)[/tex]-axis, the equation of the new graph is:
[tex]\[ \boxed{-(3)^x} \][/tex]