Mathematical expressions with LaTeX in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is LaTeX in the context of matplotlib?

LaTeX is a way to write mathematical expressions as text that matplotlib can render nicely in plots, like formulas and symbols.

beginner

How do you add a simple LaTeX expression to a matplotlib plot title?

Use dollar signs $...$ around the LaTeX code inside the title string, for example: plt.title('$x^2 + y^2 = z^2$').

beginner

What does the LaTeX code $\alpha + \beta = \gamma$ represent?

It shows the Greek letters alpha, beta, and gamma added together in a math expression.

intermediate

How can you include a fraction in a matplotlib label using LaTeX?

Use the \frac{numerator}{denominator} command inside dollar signs, for example: '$\frac{1}{2}$' to show one-half.

beginner

Why is it helpful to use LaTeX in matplotlib plots?

It makes math expressions clear and professional-looking, which helps explain data better and looks good in presentations.

How do you write a square root symbol in matplotlib using LaTeX?

A $\frac{x}{2}$

B $\sqrt{x}$

C $x^2$

D $\sum x$

The command $\sqrt{x}$ shows the square root of x.

Which of these is the correct way to write the integral symbol in matplotlib LaTeX?

A $\int f(x) \, dx$

B $\sum f(x)$

C $\frac{f(x)}{dx}$

D $\sqrt{f(x)}$

The integral symbol is written as $\int$ followed by the function and dx.

What do the dollar signs $...$ do in matplotlib text?

A They add color to the text.

B They make the text bold.

C They create a new line.

D They tell matplotlib to render the text as LaTeX math.

Dollar signs mark the start and end of LaTeX math expressions.

How would you write the expression for x squared plus y squared equals z squared in matplotlib LaTeX?

A $x^2 + y^2 = z^2$

B $x_2 + y_2 = z_2$

C $x + y = z$

D $\frac{x}{2} + \frac{y}{2} = \frac{z}{2}$

Superscript is written with ^, so x squared is $x^2$.

Which LaTeX command shows a summation symbol in matplotlib?

A $\frac{}{}$

B $\int$

C $\sum$

D $\sqrt{}$

The summation symbol is $\sum$ in LaTeX.

Explain how to add a LaTeX mathematical expression to a matplotlib plot label.

Think about how to mark math text in matplotlib.

Describe three common LaTeX commands useful for math expressions in matplotlib.

Focus on fraction, root, and sum symbols.

Practice

1. What is the correct way to include a simple fraction \(\frac{1}{2}\) in a matplotlib title using LaTeX?

easy

A. plt.title(r"$\frac{1}{2}$")

B. plt.title("$\frac{1}{2}$")

C. plt.title("\frac{1}{2}")

D. plt.title(r"\frac{1}{2}")

Solution

1. Step 1: Use raw string for LaTeX in matplotlib

   Raw strings (prefix r) prevent Python from treating backslashes as escape characters.

2. Step 2: Wrap LaTeX math expression in dollar signs

   Dollar signs tell matplotlib to interpret the string as math text.

3. Final Answer:

   plt.title(r"$\frac{1}{2}$") -> Option A

4. Quick Check:

   Raw string + $...$ = Correct LaTeX [OK]

Hint: Always use raw strings and $...$ for LaTeX in matplotlib [OK]

Common Mistakes:

• Forgetting raw string causes errors
• Missing dollar signs disables math mode
• Using plain string with backslashes causes escape errors

2. Which of the following is the correct syntax to display the integral symbol \(\int\) in a matplotlib axis label?

easy

A. plt.xlabel(r"Integral \int")

B. plt.xlabel("\int")

C. plt.xlabel("$\int$")

D. plt.xlabel(r"$\int$ Integral")

Solution

1. Step 1: Use raw string with dollar signs for LaTeX math

   Raw string avoids escape issues; dollar signs enable math mode.

2. Step 2: Place integral symbol inside dollar signs

   Integral symbol \int must be inside $...$ to render properly.

3. Final Answer:

   plt.xlabel(r"$\int$ Integral") -> Option D

4. Quick Check:

   Raw string + $\int$ = Integral symbol shown [OK]

Hint: Put math symbols inside $...$ and use raw strings [OK]

Common Mistakes:

• Not using $...$ around math symbols
• Not using raw strings causing backslash errors
• Placing math symbols outside math mode

3. What will be the output of this code snippet?

import matplotlib.pyplot as plt
plt.title(r"$\sqrt{16} = 4$")
plt.show()

medium

A. Title shows raw text including backslashes and braces

B. Title shows the square root symbol with '16 = 4' correctly formatted

C. Title shows 'sqrt{16} = 4' without square root symbol

D. Code raises a syntax error due to backslashes

Solution

1. Step 1: Raw string with $...$ enables LaTeX math rendering

   The string r"$\sqrt{16} = 4$" renders the square root symbol with 16 inside.

2. Step 2: plt.title displays the formatted math expression as title

   The plot title will show the square root symbol and the equation correctly.

3. Final Answer:

   Title shows the square root symbol with '16 = 4' correctly formatted -> Option B

4. Quick Check:

   Raw string + $\sqrt{}$ = Rendered square root [OK]

Hint: Raw string + $\sqrt{}$ shows square root symbol [OK]

Common Mistakes:

• Not using raw string causes escape errors
• Missing $...$ disables math rendering
• Expecting plain text instead of formatted math

4. Identify the error in this matplotlib code that tries to display the Greek letter alpha \(\alpha\) in the legend:

plt.plot([1,2,3], label="$\alpha$")
plt.legend()
plt.show()

medium

A. Missing raw string prefix causing backslash escape error

B. Legend function is missing parentheses

C. Label string should not use dollar signs

D. Plot data is invalid

Solution

1. Step 1: Check string for LaTeX math in label

   Using "$\alpha$" without raw string causes Python to treat \a as escape sequence.

2. Step 2: Add raw string prefix to fix backslash escape

   Change label to r"$\alpha$" to correctly render Greek letter alpha.

3. Final Answer:

   Missing raw string prefix causing backslash escape error -> Option A

4. Quick Check:

   Use raw string for LaTeX labels [OK]

Hint: Always use raw strings for LaTeX in labels [OK]

Common Mistakes:

• Forgetting raw string prefix
• Removing dollar signs disables math mode
• Misunderstanding legend syntax

5. You want to label the y-axis with the formula for the quadratic roots:
\(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)
Which matplotlib code correctly displays this formula using LaTeX?

hard

A. plt.ylabel(r"x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}")

B. plt.ylabel("$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$")

C. plt.ylabel(r"$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$")

D. plt.ylabel("x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}")

Solution

1. Step 1: Use raw string to avoid backslash escape errors

   The formula contains many backslashes, so raw string (r"...") is needed.

2. Step 2: Wrap the entire formula in dollar signs for math mode

   Dollar signs enable LaTeX math rendering in matplotlib labels.

3. Final Answer:

   plt.ylabel(r"$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$") -> Option C

4. Quick Check:

   Raw string + $...$ = Correct LaTeX formula [OK]

Hint: Use raw string and $...$ to display complex formulas [OK]

Common Mistakes:

• Not using raw string causes syntax errors
• Missing dollar signs disables math rendering
• Using plain strings with backslashes