Chapter 2: Problem 28
Make a table listing ordered pairs that satisfy each equation. Then graph the equation. Determine the domain and range, and whether \(y\) is a function of \(x .\) $$y=-x^{3}$$
Short Answer
Expert verified
The equation is a function with domain and range both \(\mathbb{R}\).
Step by step solution
01
- Understanding the equation
First, recognize that the given equation is a cubic function: \(y = -x^{3}\). In this function, for each value of \(x\), there is a corresponding value of \(y\).
02
- Create a table of ordered pairs
Select different values for \(x\) and compute the corresponding \(y\) values using the equation. For example, you can choose \(x = -2, -1, 0, 1, 2\): | \(x\) | \(y = -x^{3}\) ||------|---------------|| -2 | -(-2)^{3} = 8 || -1 | -(-1)^{3} = 1 || 0 | -(0)^{3} = 0 || 1 | -(1)^{3} = -1 || 2 | -(2)^{3} = -8 |
03
- Plot the points on a graph
Using the table from Step 2, plot the pairs (-2, 8), (-1, 1), (0, 0), (1, -1), and (2, -8) on the coordinate plane.
04
- Draw the curve
After plotting the points, draw a smooth curve through them to represent the equation \(y = -x^{3}\).
05
- Determine the domain and range
For the function \(y = -x^{3}\), the domain (all possible \(x\) values) is all real numbers, denoted as \(\mathbb{R}\). The range (all possible \(y\) values) is also all real numbers, \(\mathbb{R}\).
06
- Check if y is a function of x
For each \(x\) value, there is exactly one \(y\) value. Therefore, \(y\) is a function of \(x\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Ordered Pairs
To understand ordered pairs, remember that each pair consists of two elements: \(x\) and \(y\). For every \(x\) value you choose in the equation \(y = -x^{3}\), there is a corresponding \(y\) value. This relationship is written as \( (x, y) \).
For instance, by choosing \(x = -2\), you get \(y = 8,\) making the ordered pair \( (-2, 8) \). Repeating this process for \(x = -1, 0, 1, \text{ and}\ 2\) gives ordered pairs such as \( (-1, 1), (0, 0), (1, -1),\) and \( (2, -8) \).
In summary, an ordered pair shows how two numbers relate in a function, where the first number is from the domain and the second from the range.
For instance, by choosing \(x = -2\), you get \(y = 8,\) making the ordered pair \( (-2, 8) \). Repeating this process for \(x = -1, 0, 1, \text{ and}\ 2\) gives ordered pairs such as \( (-1, 1), (0, 0), (1, -1),\) and \( (2, -8) \).
In summary, an ordered pair shows how two numbers relate in a function, where the first number is from the domain and the second from the range.
Graphing Functions
Graphing makes it easier to understand the shape and behavior of a function. For the cubic function \(y = -x^{3}\), the process begins with plotting the ordered pairs found in the previous step.
Follow these tips for graphing:
Follow these tips for graphing:
- Locate and mark each \( (x, y) \) point on the coordinate plane. For instance, plot \( (-2, 8) \) by moving \ -2 \ units on the x-axis and \ 8 \ units on the y-axis.
- Continue plotting all pairs such as \( (-1, 1), (0, 0), (1, -1), \text{ and}\ (2, -8) \).
- Once all points are plotted, draw a smooth curve passing through them. This curve represents the cubic function accurately.
Domain and Range
The domain and range of a function define the set of all possible input and output values, respectively.
For the cubic function \(y = -x^{3}\):
For the cubic function \(y = -x^{3}\):
- Domain: Since any real number can be cubed, the domain is all real numbers, denoted as \( \text{R} \).
- Range: Likewise, since a cubic function can output any real number, the range is also \( \text{R} \).
Function Analysis
Analyzing the function \(y = -x^{3}\) provides a deeper insight into its properties and behavior.
One key aspect is understanding if \(y\) is a function of \(x\). Simply put, for every value of \(x\) in a function, there should be exactly one corresponding \(y\) value. In the case of \(y = -x^{3}\), this relationship holds true because:
One key aspect is understanding if \(y\) is a function of \(x\). Simply put, for every value of \(x\) in a function, there should be exactly one corresponding \(y\) value. In the case of \(y = -x^{3}\), this relationship holds true because:
- For every \(x\) value, computing \(-x^{3}\) gives a unique \(y\) value.
- This indicates a clear one-to-one correspondence.