How does the graph of [tex]$y=3^{-x}$[/tex] compare to the graph of [tex]$y=\left(\frac{1}{3}\right)^{-x}$[/tex]?

A. The graphs are the same.
B. The graphs are reflected across the [tex]$x$[/tex]-axis.
C. The graphs are reflected across the [tex]$y$[/tex]-axis.



Answer :

To understand the relationship between the graphs of [tex]\( y = 3^{-x} \)[/tex] and [tex]\( y = \left(\frac{1}{3}\right)^x \)[/tex], let's first rewrite [tex]\( y = 3^{-x} \)[/tex] in a more familiar form.

1. Recall the negative exponent rule:
[tex]\[ 3^{-x} = \left(\frac{1}{3}\right)^x \][/tex]

2. This shows us that the function [tex]\( y = 3^{-x} \)[/tex] is equivalent to [tex]\( y = \left(\frac{1}{3}\right)^x \)[/tex].

3. Next, let's consider the graph of [tex]\( y = \left(\frac{1}{3}\right)^x \)[/tex]:
[tex]\[ y = \left(\frac{1}{3}\right)^x \][/tex]
This is an exponential decay function, where the base [tex]\( \frac{1}{3} \)[/tex] is a fraction between 0 and 1.

4. Now, let's recall the behavior of exponential functions. For [tex]\( y = 3^x \)[/tex], the graph is an exponential growth function. The graph of [tex]\( y = \left(\frac{1}{3}\right)^x \)[/tex] is reflected across the y-axis compared to [tex]\( y = 3^x \)[/tex]. This is because [tex]\( \left(\frac{1}{3}\right)^x \)[/tex] is the same as [tex]\( 3^{-x} \)[/tex]. In other words, the exponent's sign change corresponds to a reflection over the y-axis.

Therefore, the graphs of [tex]\( y = 3^{-x} \)[/tex] and [tex]\( y = \left(\frac{1}{3}\right)^x \)[/tex] are indeed reflections across the [tex]\( y \)[/tex]-axis.

Thus, the correct answer is:
The graphs are reflected across the [tex]\( y \)[/tex]-axis.