Chapter 10: Problem 21
Graph each exponential function. $$ g(x)=\left(\frac{1}{3}\right)^{x} $$
Short Answer
Expert verified
The graph of \( g(x) = \left(\frac{1}{3}\right)^{x} \) is a decreasing exponential function with a horizontal asymptote at \( y = 0 \).
Step by step solution
01
Identify the Exponential Function
The given exponential function is \( g(x) = \left(\frac{1}{3}\right)^{x} \). Here, the base of the exponential function is \( \frac{1}{3} \).
02
Create a Table of Values
To graph the function, create a table of values for \( x \) and \( g(x) \). Choose some values for \( x \), both positive and negative, to see the behavior of the function.For example:\( x = -2, -1, 0, 1, 2 \)Calculate \( g(x) \) for each \( x \):\( g(-2) = \left(\frac{1}{3}\right)^{-2} = 9 \)\( g(-1) = \left(\frac{1}{3}\right)^{-1} = 3 \)\( g(0) = \left(\frac{1}{3}\right)^{0} = 1 \)\( g(1) = \left(\frac{1}{3}\right)^{1} = \frac{1}{3} \)\( g(2) = \left(\frac{1}{3}\right)^{2} = \frac{1}{9} \)
03
Plot the Points
Using the table of values, plot the points on a coordinate plane. The points are:(\( -2, 9 \)), (\( -1, 3 \)), (\( 0, 1 \)), (\( 1, \frac{1}{3} \)), (\( 2, \frac{1}{9} \)).
04
Draw the Graph
Connect the points with a smooth curve to complete the graph of the exponential function \( g(x) = \left(\frac{1}{3}\right)^{x} \). Note that as \( x \) increases, \( g(x) \) decreases toward 0. As \( x \) decreases, \( g(x) \) increases exponentially.
05
Analyze the Graph
The graph is a decreasing exponential function since the base \( \frac{1}{3} \) is between 0 and 1. The horizontal asymptote of the graph is the x-axis (\( y = 0 \)).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Plotting Exponential Functions
Plotting exponential functions involves graphing the set of solutions to a function of the form \(g(x) = a^x\), where \(a\) is a constant. In this exercise, the function is \(g(x)=\frac{1}{3}^x\). The process starts with creating a table of values.
For instance, you could choose \(x = -2, -1, 0, 1, 2\). This allows you to see the behavior of the function with both positive and negative values of \(x\).
Once you have your input values, calculate the corresponding \(g(x)\) values:
The curve will exhibit a distinct shape typical of exponential functions.
For instance, you could choose \(x = -2, -1, 0, 1, 2\). This allows you to see the behavior of the function with both positive and negative values of \(x\).
Once you have your input values, calculate the corresponding \(g(x)\) values:
- When \(x = -2\), \(g(-2) = 9\)
- When \(x = -1\), \(g(-1) = 3\)
- When \(x = 0\), \(g(0) = 1\)
- When \(x = 1\), \(g(1) = \frac{1}{3}\)
- When \(x = 2\), \(g(2) = \frac{1}{9}\)
- (-2, 9)
- (-1, 3)
- (0, 1)
- (1, 1/3)
- (2, 1/9)
The curve will exhibit a distinct shape typical of exponential functions.
Decreasing Exponential Functions
A decreasing exponential function is characterized by its base being between 0 and 1.
In our example, \(\frac{1}{3}\) is the base. Since it's less than 1 and greater than 0, the function \(g(x) = \frac{1}{3}^x\) decreases as \(x\) increases. This tells us something important about the function's behavior.
Here are some key features to note:
In our example, \(\frac{1}{3}\) is the base. Since it's less than 1 and greater than 0, the function \(g(x) = \frac{1}{3}^x\) decreases as \(x\) increases. This tells us something important about the function's behavior.
Here are some key features to note:
- As \(x\) goes to positive infinity, \(g(x)\) approaches 0.
- For increasing values of \(x\), \(g(x)\) gets smaller and smaller.
- Conversely, as \(x\) becomes more negative, \(g(x)\) grows larger.
Horizontal Asymptote
In the context of exponential functions, the horizontal asymptote is a line that the graph approaches but never touches.
For the function \(g(x) = \frac{1}{3}^x\), we observe that as \(x\) increases indefinitely, the value of \(g(x)\) gets closer and closer to 0 but never actually becomes 0.
This is why the line \(y = 0\) (or the x-axis) is considered the horizontal asymptote. Some key points:
For the function \(g(x) = \frac{1}{3}^x\), we observe that as \(x\) increases indefinitely, the value of \(g(x)\) gets closer and closer to 0 but never actually becomes 0.
This is why the line \(y = 0\) (or the x-axis) is considered the horizontal asymptote. Some key points:
- The function \(g(x)\) will decrease infinitely but will never cross the x-axis.
- The horizontal asymptote represents the lower boundary of the function's value.
- This line acts as a reference point to understand how the function behaves as \(x\) grows larger.