Chapter 5: Problem 2
Graph each equation. $$f(x)=4^{x}$$
Short Answer
Expert verified
Graph an increasing curve passing through (0,1) with a horizontal asymptote at y=0.
Step by step solution
01
Identify the Type of Function
Recognize that the function given, \( f(x) = 4^x \), is an exponential function. In this function, the base is 4 and the exponent is \( x \).
02
Determine Key Characteristics
Identify key characteristics of the exponential function: the domain is all real numbers, the range is \((0, +\infty)\), and the y-intercept is at the point \( (0,1) \). The graph is continuously increasing as the base \(4\) is greater than 1.
03
Plot Key Points
Calculate key points by substituting a few values for \(x\). For example: \(f(-1) = 4^{-1} = \frac{1}{4}\), \(f(0) = 4^0 = 1\), \(f(1) = 4^1 = 4\), and \(f(2) = 4^2 = 16\). Use these points to guide your graph plotting.
04
Sketch the Graph
Based on the calculated points, plot them on a coordinate plane. The points should reflect an exponential curve starting from low values on the y-axis (at and near negative x-values) to high y-values as x increases. The graph should pass through the points (0,1), (1,4), (2,16), and continue rising steeply.
05
Draw Asymptote
Identify the horizontal asymptote of the function. Since \( f(x) = 4^x \) approaches 0 as \( x \to -\infty \), draw a horizontal asymptote along the x-axis, at \( y = 0 \).
06
Review Graph Properties
Review the curve to ensure it is a smooth, continuous line that goes from left to right, approaching the horizontal asymptote at \( y = 0 \) and rising sharply without bound as \( x \) increases. Make sure the graph aligns with the key characteristics identified earlier.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphing
Graphing an exponential function like \( f(x) = 4^x \) involves understanding its general curve structure on a coordinate plane. The function increases rapidly as \( x \) increases because the base 4 is greater than 1. To accurately graph this function, it helps to plot some key points. For instance:
Put these points on the graph. They should create a curve that begins gently and then climbs quickly as \( x \) becomes larger. These points are guiding markers to help sketch the characteristic exponential shape, rising more steeply for increasing \( x \) values.
- When \( x = -1 \), \( f(x) = \frac{1}{4} \).
- When \( x = 0 \), \( f(x) = 1 \) (as the value of any number raised to the zero power is 1).
- When \( x = 1 \), \( f(x) = 4 \).
- At \( x = 2 \), \( f(x) = 16 \).
Put these points on the graph. They should create a curve that begins gently and then climbs quickly as \( x \) becomes larger. These points are guiding markers to help sketch the characteristic exponential shape, rising more steeply for increasing \( x \) values.
Function Characteristics
The characteristics of an exponential function such as \( f(x) = 4^x \) are distinct and unique. The domain of an exponential function is all real numbers, meaning \( x \) can take any value from negative infinity to positive infinity. However, the range is different. For exponential growth functions, the range is \((0, +\infty)\), which means all output values of the function are positive.
An essential characteristic is that this function has a y-intercept at \( (0, 1) \), indicating the point where the graph crosses the y-axis. Since the base 4 is greater than 1, the function is increasing, meaning as \( x \) gets larger, \( f(x) \) also becomes larger without bound. These properties make exponential functions powerful for modeling growth processes, compounding phenomena, and other similar real-world situations.
An essential characteristic is that this function has a y-intercept at \( (0, 1) \), indicating the point where the graph crosses the y-axis. Since the base 4 is greater than 1, the function is increasing, meaning as \( x \) gets larger, \( f(x) \) also becomes larger without bound. These properties make exponential functions powerful for modeling growth processes, compounding phenomena, and other similar real-world situations.
Asymptotes
In the context of exponential functions, an asymptote is a line that the graph of the function approaches but never actually touches. For the function \( f(x) = 4^x \), the graph has a horizontal asymptote. This is a line located at \( y = 0 \), or the x-axis. As \( x \) tends to negative infinity, the value of \( 4^x \) approaches zero but never reaches it.
Identifying the asymptote is vital because it shows the boundary behavior of the graph as \( x \) decreases. Essentially, no matter how much \( x \) decreases, \( f(x) \) remains positive and approaches, but does not reach, zero. Draw this asymptote on your graph as a dashed line along the x-axis. Observing the asymptote helps in predicting and understanding the long-term behavior of the function.
Identifying the asymptote is vital because it shows the boundary behavior of the graph as \( x \) decreases. Essentially, no matter how much \( x \) decreases, \( f(x) \) remains positive and approaches, but does not reach, zero. Draw this asymptote on your graph as a dashed line along the x-axis. Observing the asymptote helps in predicting and understanding the long-term behavior of the function.