How to Write Piecewise Functions in LaTeX: A Step-by-Step Guide (2025)

Have you ever wanted to write a piecewise function in LaTeX? Maybe you’re a student who’s just been introduced to the concept, or maybe you’re a programmer who’s looking for a way to represent a function that has multiple pieces. Whatever the case may be, I’m here to help.

In this article, I’ll show you how to write piecewise functions in LaTeX using the \piecewise command. I’ll also provide some examples of how to use this command to create different types of piecewise functions. So if you’re ready to learn how to write piecewise functions in LaTeX, let’s get started!

In mathematics, a piecewise function is a function that is defined in different parts of its domain. This means that the function may have different formulas for different values of its input. Piecewise functions are often used to model real-world phenomena that can be described by different equations in different regions.

For example, a function that models the temperature of a room might be defined as follows:

\begin{cases}
T(x) = 72^{\circ}F & \text{if } x \leq 6am \\
T(x) = 68^{\circ}F & \text{if } 6am < x \leq 6pm \\ T(x) = 75^{\circ}F & \text{if } 6pm < x \leq 10pm \\ T(x) = 72^{\circ}F & \text{if } 10pm < x\end{cases}This function is defined differently for each of the four time periods: morning, afternoon, evening, and night. This allows the function to accurately model the different temperatures that occur during each time period.**Syntax for piecewise functions in LaTeX**The syntax for a piecewise function in LaTeX is as follows:\begin{cases} f(x) = a & \text{if } x \leq b \\ f(x) = c & \text{if } x > b
\end{cases}

Where `a`, `b`, and `c` are constants.

The `\begin{cases}` and `\end{cases}` commands are used to create a set of brackets, and the `&` symbol is used to separate the different cases of the function. The `\text{if}` command is used to indicate the condition that must be met for the function to evaluate to a particular value.

For example, the following code defines a piecewise function that returns the value `1` if `x` is less than or equal to `0`, and the value `2` if `x` is greater than `0`:

\begin{cases}
f(x) = 1 & \text{if } x \leq 0 \\
f(x) = 2 & \text{if } x > 0
\end{cases}

**Examples of piecewise functions in LaTeX**

Here are some examples of piecewise functions in LaTeX:

\begin{cases}
f(x) = x^2 & \text{if } x \leq 0 \\
f(x) = x & \text{if } x > 0
\end{cases}

This function returns the square of `x` if `x` is less than or equal to `0`, and the value of `x` if `x` is greater than `0`.

\begin{cases}
f(x) = \frac{1}{x} & \text{if } x \neq 0 \\
f(x) = 0 & \text{if } x = 0
\end{cases}

This function returns the reciprocal of `x` if `x` is not equal to `0`, and the value `0` if `x` is equal to `0`.

\begin{cases}
f(x) = \sin(x) & \text{if } x \leq \pi \\
f(x) = \cos(x) & \text{if } x > \pi
\end{cases}

This function returns the sine of `x` if `x` is less than or equal to `\pi`, and the cosine of `x` if `x` is greater than `\pi`.

Piecewise functions are a powerful tool for modeling real-world phenomena. They can be used to describe functions that have different behaviors in different regions of their domain. LaTeX provides a simple and concise syntax for defining piecewise functions, making them easy to use and understand.

Piecewise functions are functions that are defined in different parts of their domain. This can be useful for modeling functions that have discontinuities or multiple branches. In LaTeX, piecewise functions can be written using the `cases` environment.

To write a piecewise function in LaTeX, use the following syntax:

\begin{cases}
f(x) = g(x) & \text{if } x \in A \\
f(x) = h(x) & \text{if } x \in B \\
\vdots & \vdots \\
f(x) = p(x) & \text{if } x \in P
\end{cases}

where `A`, `B`, `P`, etc. are sets of values that define the domain of the function. The function `g(x)` is evaluated for values of `x` in `A`, the function `h(x)` is evaluated for values of `x` in `B`, and so on.

For example, the following code defines a piecewise function that is equal to `x^2` for values of `x` less than or equal to 0, and equal to `x` for values of `x` greater than 0:

\begin{cases}
f(x) = x^2 & \text{if } x \leq 0 \\
f(x) = x & \text{if } x > 0
\end{cases}

You can also use the `cases` environment to define piecewise functions with multiple branches. For example, the following code defines a piecewise function that is equal to `x^2` for values of `x` less than or equal to 0, equal to `x` for values of `x` between 0 and 1, and equal to `x^3` for values of `x` greater than 1:

\begin{cases}
f(x) = x^2 & \text{if } x \leq 0 \\
f(x) = x & \text{if } 0 < x \leq 1 \\ f(x) = x^3 & \text{if } x > 1
\end{cases}

Piecewise functions can be used to model a variety of different functions, including step functions, discontinuous functions, and even functions with multiple local extrema. They can also be used to simplify the notation of more complex functions.

**Example:**

The following code defines a piecewise function that models the voltage drop across a resistor as a function of current:

\begin{cases}
V(I) = IR & \text{if } I \leq I_c \\
V(I) = I_cR + (I – I_c)R_d & \text{if } I > I_c
\end{cases}

where `V` is the voltage drop, `I` is the current, `R` is the resistance, `I_c` is the critical current, and `R_d` is the dynamic resistance.

This function models the behavior of a resistor as the current increases. For currents less than or equal to the critical current, the voltage drop is linear with the current. For currents greater than the critical current, the voltage drop increases more rapidly with the current.

:

Piecewise functions are a powerful tool for modeling a variety of different functions. They can be used to simplify the notation of more complex functions, and they can also be used to model functions with discontinuities or multiple branches.

Q: How do I write a piecewise function in LaTeX?

A: To write a piecewise function in LaTeX, you can use the following syntax:

\begin{cases}
f(x) = a & \text{if } x \leq c \\
f(x) = b & \text{if } x > c
\end{cases}

where `a` and `b` are the values of the function for `x` less than or equal to `c` and greater than `c`, respectively.

Q: What are the different types of piecewise functions?

A: There are three main types of piecewise functions:

• Linear piecewise functions: These functions are defined by a series of linear equations, each of which is valid for a specific interval of `x` values.
• Quadratic piecewise functions: These functions are defined by a series of quadratic equations, each of which is valid for a specific interval of `x` values.
• Cubic piecewise functions: These functions are defined by a series of cubic equations, each of which is valid for a specific interval of `x` values.

Q: How do I plot a piecewise function in LaTeX?

A: To plot a piecewise function in LaTeX, you can use the following syntax:

\begin{tikzpicture}
\begin{axis}[
xlabel=x,
ylabel=f(x),
xmin=-5,
xmax=5,
ymin=-5,
ymax=5
]
\addplot[domain=-5:5, samples=100] {
\begin{cases}
0 & \text{if } x \leq 0 \\
x & \text{if } x > 0
\end{cases}
};
\end{axis}
\end{tikzpicture}

This will produce the following plot:

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