Using a Graphing Calculator or CAS

Oct 13, 2025 by wbrum.org 51 views

Introduction

Piecewise-defined functions are a type of function that is defined by multiple sub-functions, each applied to a specific interval of the domain. These functions are commonly used in mathematics, physics, and engineering to model real-world phenomena. In this article, we will focus on graphing piecewise-defined functions, with a specific example of the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ .

Understanding Piecewise-Defined Functions

A piecewise-defined function is a function that is defined by multiple sub-functions, each applied to a specific interval of the domain. The function is typically written in the form:

f(x) = \begin{cases} f_1(x) & \text{if } x \in D_1 \\ f_2(x) & \text{if } x \in D_2 \\ \vdots & \text{if } x \in D_n \end{cases}

where $f_1(x), f_2(x), \ldots, f_n(x)$ are the sub-functions, and $D_1, D_2, \ldots, D_n$ are the intervals of the domain.

Graphing Piecewise-Defined Functions

Graphing a piecewise-defined function involves graphing each sub-function separately and then combining the graphs to form the final graph. The key to graphing piecewise-defined functions is to identify the intervals of the domain and the corresponding sub-functions.

Step 1: Identify the Intervals of the Domain

The first step in graphing a piecewise-defined function is to identify the intervals of the domain. In the case of the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ , the intervals of the domain are $(-\infty, 2]$ and $(2, \infty)$ .

Step 2: Graph Each Sub-Function

The next step is to graph each sub-function separately. For the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ , we need to graph the two sub-functions $f_1(x) = -3-x$ and $f_2(x) = -7+2x$ .

Graphing $f_1(x) = -3-x$

The graph of $f_1(x) = -3-x$ is a straight line with a slope of -1 and a y-intercept of -3. The graph is a decreasing function, meaning that as x increases, f(x) decreases.

Graphing $f_2(x) = -7+2x$

The graph of $f_2(x) = -7+2x$ is a straight line with a slope of 2 and a y-intercept of -7. The graph is an increasing function, meaning that as x increases, f(x) increases.

Step 3: Combine the Graphs

The final step is to combine the graphs of the two sub-functions to form the final graph of the piecewise-defined function. The graph of $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ is a piecewise-defined function that consists of two straight lines, one with a slope of -1 and a y-intercept of -3, and the other with a slope of 2 and a y-intercept of -7.

Graphing Piecewise-Defined Functions: A Visual Approach

Graphing piecewise-defined functions can be a challenging task, but it can be made easier by using a visual approach. One way to visualize the graph of a piecewise-defined function is to use a graphing calculator or a computer algebra system (CAS).

Using a Graphing Calculator or CAS

A graphing calculator or CAS can be used to graph piecewise-defined functions by entering the function in the calculator or CAS and then using the graphing feature to visualize the graph.

Graphing Piecewise-Defined Functions: A Step-by-Step Approach

Graphing piecewise-defined functions can be a challenging task, but it can be made easier by following a step-by-step approach. Here are the steps to graph a piecewise-defined function:

Identify the intervals of the domain.
Graph each sub-function separately.
Combine the graphs of the sub-functions to form the final graph.

Conclusion

Graphing piecewise-defined functions is a challenging task, but it can be made easier by following a step-by-step approach. By identifying the intervals of the domain, graphing each sub-function separately, and combining the graphs of the sub-functions, we can visualize the graph of a piecewise-defined function. In this article, we have focused on graphing the piecewise-defined function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ , and we have shown how to use a graphing calculator or CAS to visualize the graph.

References

[1] "Graphing Piecewise-Defined Functions" by Math Open Reference.
[2] "Graphing Piecewise-Defined Functions" by Purplemath.
[3] "Graphing Piecewise-Defined Functions" by Khan Academy.

Additional Resources

[1] "Graphing Piecewise-Defined Functions" by Wolfram Alpha.
[2] "Graphing Piecewise-Defined Functions" by Desmos.
[3] "Graphing Piecewise-Defined Functions" by GeoGebra.

Frequently Asked Questions

Q: What is a piecewise-defined function?
A: A piecewise-defined function is a function that is defined by multiple sub-functions, each applied to a specific interval of the domain.
Q: How do I graph a piecewise-defined function?
A: To graph a piecewise-defined function, you need to identify the intervals of the domain, graph each sub-function separately, and combine the graphs of the sub-functions to form the final graph.
Q: What is the difference between a piecewise-defined function and a continuous function?
A: A piecewise-defined function is a function that is defined by multiple sub-functions, while a continuous function is a function that is defined by a single function and has no gaps or jumps in its graph.
Graphing Piecewise-Defined Functions: A Q&A Article =====================================================

Introduction

Graphing piecewise-defined functions can be a challenging task, but it can be made easier by following a step-by-step approach. In this article, we will answer some of the most frequently asked questions about graphing piecewise-defined functions.

Q: What is a piecewise-defined function?

A: A piecewise-defined function is a function that is defined by multiple sub-functions, each applied to a specific interval of the domain. For example, the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ is a piecewise-defined function.

Q: How do I graph a piecewise-defined function?

A: To graph a piecewise-defined function, you need to identify the intervals of the domain, graph each sub-function separately, and combine the graphs of the sub-functions to form the final graph. Here are the steps to graph a piecewise-defined function:

Identify the intervals of the domain.
Graph each sub-function separately.
Combine the graphs of the sub-functions to form the final graph.

Q: What is the difference between a piecewise-defined function and a continuous function?

A: A piecewise-defined function is a function that is defined by multiple sub-functions, while a continuous function is a function that is defined by a single function and has no gaps or jumps in its graph. For example, the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ is a piecewise-defined function, while the function $f(x) = 2x$ is a continuous function.

Q: How do I determine the intervals of the domain for a piecewise-defined function?

A: To determine the intervals of the domain for a piecewise-defined function, you need to look at the function definition and identify the intervals where each sub-function is applied. For example, in the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ , the intervals of the domain are $(-\infty, 2]$ and $(2, \infty)$ .

Q: How do I graph each sub-function separately?

A: To graph each sub-function separately, you need to graph the function on the interval where it is defined. For example, to graph the sub-function $f_1(x) = -3-x$ on the interval $(-\infty, 2]$ , you need to graph the function on this interval.

Q: How do I combine the graphs of the sub-functions to form the final graph?

A: To combine the graphs of the sub-functions to form the final graph, you need to graph each sub-function on its respective interval and then combine the graphs to form the final graph. For example, to graph the function $f(x) = \begin{cases} -3-x & \text{if } x \leq 2 \\ -7+2x & \text{if } x \ \textgreater \ 2 \end{cases}$ , you need to graph the sub-function $f_1(x) = -3-x$ on the interval $(-\infty, 2]$ and the sub-function $f_2(x) = -7+2x$ on the interval $(2, \infty)$ , and then combine the graphs to form the final graph.

Q: What are some common mistakes to avoid when graphing piecewise-defined functions?

A: Some common mistakes to avoid when graphing piecewise-defined functions include:

Not identifying the intervals of the domain correctly.
Not graphing each sub-function separately.
Not combining the graphs of the sub-functions correctly.
Not checking for continuity and discontinuity.

Q: How can I use technology to graph piecewise-defined functions?

A: You can use technology such as graphing calculators or computer algebra systems (CAS) to graph piecewise-defined functions. These tools can help you to graph the function and identify any discontinuities or gaps in the graph.

Q: What are some real-world applications of piecewise-defined functions?

A: Piecewise-defined functions have many real-world applications, including:

Modeling population growth and decline.
Modeling economic systems.
Modeling physical systems.
Modeling biological systems.

Conclusion

Graphing piecewise-defined functions can be a challenging task, but it can be made easier by following a step-by-step approach. By identifying the intervals of the domain, graphing each sub-function separately, and combining the graphs of the sub-functions, we can visualize the graph of a piecewise-defined function. In this article, we have answered some of the most frequently asked questions about graphing piecewise-defined functions.

References

[1] "Graphing Piecewise-Defined Functions" by Math Open Reference.
[2] "Graphing Piecewise-Defined Functions" by Purplemath.
[3] "Graphing Piecewise-Defined Functions" by Khan Academy.

Additional Resources

[1] "Graphing Piecewise-Defined Functions" by Wolfram Alpha.
[2] "Graphing Piecewise-Defined Functions" by Desmos.
[3] "Graphing Piecewise-Defined Functions" by GeoGebra.

Frequently Asked Questions

Q: What is a piecewise-defined function?
A: A piecewise-defined function is a function that is defined by multiple sub-functions, each applied to a specific interval of the domain.
Q: How do I graph a piecewise-defined function?
A: To graph a piecewise-defined function, you need to identify the intervals of the domain, graph each sub-function separately, and combine the graphs of the sub-functions to form the final graph.
Q: What is the difference between a piecewise-defined function and a continuous function?
A: A piecewise-defined function is a function that is defined by multiple sub-functions, while a continuous function is a function that is defined by a single function and has no gaps or jumps in its graph.