Chapter 0: Problem 44
Graph each function by plotting points and state the domain and range. If you have a graphing calculator, use it to check your results. $$ y=2|x| $$
Short Answer
Expert verified
Domain: \[ (-\infty, \infty) \] Range: \[ [0, \infty) \].
Step by step solution
01
Understand the Function
First, understand that the given function is an absolute value function, scaled by a factor of 2. The equation is: \[ y = 2|x| \].
02
Create a Table of Values
Choose a set of x-values to plug into the function and solve for the corresponding y-values. For example, select x-values: -3, -2, -1, 0, 1, 2, 3.
03
Calculate y-values
Using the chosen x-values, calculate the corresponding y-values: \[ y = 2|x| \] For x = -3, y = 2|-3| = 6 For x = -2, y = 2|-2| = 4 For x = -1, y = 2|-1| = 2 For x = 0, y = 0 For x = 1, y = 2 For x = 2, y = 4 For x = 3, y = 6
04
Plot the Points
Plot the points you calculated on a coordinate plane: (-3, 6), (-2, 4), (-1, 2), (0, 0), (1, 2), (2, 4), (3, 6).
05
Draw the Graph
Connect the plotted points to form a V-shaped graph. The vertex of the graph is at (0,0), and it opens upwards.
06
State the Domain
The domain of the function \( y = 2|x| \) is all real numbers: \[ (-\infty, \infty) \].
07
State the Range
The range of the function \( y = 2|x| \) is all non-negative real numbers: \[ [0, \infty) \].
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
plotting points
To graph an absolute value function like \[ y = 2|x| \], you'll first want to plot points. Start with choosing a set of x-values, like \(-3, -2, -1, 0, 1, 2, 3\). Calculate the corresponding y-values by plugging each x-value into the function. Here’s what you get:
- For x = -3, y = 2|-3| = 6
- For x = -2, y = 2|-2| = 4
- For x = -1, y = 2|-1| = 2
- For x = 0, y = 0
- For x = 1, y = 2
- For x = 2, y = 4
- For x = 3, y = 6
domain and range
Determining the domain and range of the function \[ y = 2|x| \] is an essential part of graphing. The domain refers to all the possible x-values that you can input into the function. For absolute value functions, you can input any real number, so the domain is \((-\infty, \infty)\), which means all real numbers.
The range refers to all the possible y-values that can result from the function. Since \[ y = 2|x| \] multiplies the absolute value of x by 2, the smallest value y can take is 0, which occurs when x is 0. As x moves away from 0 in both the positive and negative directions, y increases. Therefore, the range is \([0, \infty)\), which includes zero and all positive real numbers.
The range refers to all the possible y-values that can result from the function. Since \[ y = 2|x| \] multiplies the absolute value of x by 2, the smallest value y can take is 0, which occurs when x is 0. As x moves away from 0 in both the positive and negative directions, y increases. Therefore, the range is \([0, \infty)\), which includes zero and all positive real numbers.
absolute value function
An absolute value function graphs a special kind of equation that involves the absolute value operation, denoted as |x|. The absolute value of a number is its distance from zero on the number line, without considering direction. For example, |3| = 3 and |-3| = 3.
In our given absolute value function \[ y = 2|x| \], we see a V-shaped graph. The vertex or the lowest point of this graph is at (0,0). The graph opens upwards because the absolute value function returns non-negative values, and the factor of 2 outside the absolute value means the graph is vertically stretched by a factor of 2 compared to \ |x| \.
Understanding the role of the absolute value and any constant multiplication is crucial. Here are some key points:
In our given absolute value function \[ y = 2|x| \], we see a V-shaped graph. The vertex or the lowest point of this graph is at (0,0). The graph opens upwards because the absolute value function returns non-negative values, and the factor of 2 outside the absolute value means the graph is vertically stretched by a factor of 2 compared to \ |x| \.
Understanding the role of the absolute value and any constant multiplication is crucial. Here are some key points:
- The absolute value creates a V-shape because it reflects all negative x-values into positives.
- The number outside the absolute value, in this case, 2, affects the stretching. A larger number makes the V-shape narrower, while a smaller number would make it wider.