Chapter 11: Problem 42
For Problems \(35-52\), graph each exponential function. $$ f(x)=\left(\frac{2}{3}\right)^{x} $$
Short Answer
Expert verified
The graph of \( f(x) = \left(\frac{2}{3}\right)^x \) is an exponential decay curve that decreases as \( x \) increases.
Step by step solution
01
Identify the Type of Function
The function is an exponential function of the form \( f(x) = a^x \). In this case, \( a \) is \( \frac{2}{3} \). Since \( a < 1 \), the function represents exponential decay.
02
Create a Table of Values
Choose a few values for \( x \) to calculate corresponding \( f(x) \) values. For example:- \( x = -2 \): \( f(-2) = \left(\frac{2}{3}\right)^{-2} = \left(\frac{3}{2}\right)^{2} = \frac{9}{4}\)- \( x = -1 \): \( f(-1) = \left(\frac{3}{2}\right)^1 = \frac{3}{2} \)- \( x = 0 \): \( f(0) = \left(\frac{2}{3}\right)^0 = 1 \)- \( x = 1 \): \( f(1) = \left(\frac{2}{3}\right)^1 = \frac{2}{3} \)- \( x = 2 \): \( f(2) = \left(\frac{2}{3}\right)^2 = \frac{4}{9} \)
03
Plot the Points
Using the table of values, plot the points \((-2, \frac{9}{4}), (-1, \frac{3}{2}), (0, 1), (1, \frac{2}{3}), (2, \frac{4}{9})\) on a coordinate plane. These points represent the function's behavior.
04
Draw the Graph
Connect the plotted points with a smooth curve. As \( x \) approaches negative infinity, the graph approaches zero, indicating the function decreases as \( x \) increases. The curve should show a decreasing trend from left to right.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
graphing exponential functions
Graphing exponential functions involves plotting two variables, typically denoted as \( x \) and \( f(x) \). The function \( f(x) = \left( \frac{2}{3} \right)^x \) is an exponential function, where the exponent \( x \) determines the value of the function.
To graph such a function, a step-by-step method is followed:
To graph such a function, a step-by-step method is followed:
- Choose a set of \( x \) values to generate corresponding \( f(x) \) values, forming a table of values (more on this later).
- Use these computed points to plot them on a coordinate plane.
- Connect these points smoothly to represent the trend accurately.
exponential decay
Exponential decay occurs in exponential functions where the base of the exponent is between 0 and 1, such as \( \frac{2}{3} \). This results in the function output decreasing as \( x \) increases.
In the specific function \( f(x) = \left( \frac{2}{3} \right)^x \), the base is less than one, indicating decay:
In the specific function \( f(x) = \left( \frac{2}{3} \right)^x \), the base is less than one, indicating decay:
- This means that as time (or \( x \)) increases, the value of \( f(x) \) gets closer and closer to zero.
- It represents processes such as radioactive decay or depreciation in value over time.
coordinate plane
The coordinate plane, essential for graphing functions, consists of two axes: the horizontal \( x \)-axis and the vertical \( y \)-axis. Points on this plane have coordinates \((x, y)\), where \( y \) corresponds to \( f(x) \).
For an exponential function like \( f(x) = \left( \frac{2}{3} \right)^x \), plotting it involves identifying specific points using a table of values:
For an exponential function like \( f(x) = \left( \frac{2}{3} \right)^x \), plotting it involves identifying specific points using a table of values:
- Select points calculated from the function, such as \((-2, \frac{9}{4})\), and plot each one on the plane.
- The plane allows for a visual representation of how \( f(x) \) changes as \( x \) changes.
table of values
A table of values is a fundamental tool in graphing functions. It helps establish the relationship between \( x \) and \( f(x) \) by calculating and listing several points:
- Choose \( x \) values that adequately capture the function's behavior, both negative and positive.
- Calculate corresponding \( f(x) \) values for each \( x \).
- List the results as pairs, such as \((x, f(x))\), that can be used for plotting.