Mathematical expressions with LaTeX in Matplotlib - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display a simple LaTeX expression on a plot.

Matplotlib

import matplotlib.pyplot as plt
plt.text(0.5, 0.5, r'$[1]$', fontsize=20, ha='center')
plt.axis('off')
plt.show()

Drag options to blanks, or click blank then click option'

A\alpha + beta = \gamma

Balpha + beta = gamma

Calpha + \beta = gamma

D\alpha + \beta = \gamma

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the backslash before Greek letters.

Not using raw string notation r'' causing escape errors.

Omitting the $ signs around the LaTeX expression.

The LaTeX expression must use backslash commands for Greek letters inside the math mode delimiters $...$.

2fill in blank

medium

Complete the code to plot the quadratic formula using LaTeX in the title.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [1, 4, 9])
plt.title(r'Quadratic formula: $x = \frac[1]{{2a}}$')
plt.show()

Drag options to blanks, or click blank then click option'

A-b \pm \sqrt{b^2 + 4ac}

Bb \pm \sqrt{b^2 - 4ac}

C-b \pm \sqrt{b^2 - 4ac}

Db \pm \sqrt{b^2 + 4ac}

Attempts:

3 left

💡 Hint

Common Mistakes

Using plus instead of minus before b.

Using plus instead of minus inside the square root.

Forgetting \pm symbol.

The quadratic formula numerator is '-b ± sqrt(b^2 - 4ac)'.

3fill in blank

hard

Fix the error in the LaTeX expression to correctly display the integral in the plot label.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([0, 1], [0, 1])
plt.xlabel(r'Integral: $\int_0^1 f(x) dx = [1]$')
plt.show()

Drag options to blanks, or click blank then click option'

A\frac{1}{2}

B1/2

C\frac12

D\int_0^1 f(x) dx

Attempts:

3 left

💡 Hint

Common Mistakes

Writing fractions without \frac{}{} syntax.

Repeating the integral expression instead of the result.

Using incomplete fraction commands like \frac12.

The integral from 0 to 1 of f(x) dx equals 1/2, written as \frac{1}{2} in LaTeX.

4fill in blank

hard

Fill both blanks to create a LaTeX expression for the sum of squares in the plot text.

Matplotlib

import matplotlib.pyplot as plt
plt.text(0.5, 0.5, r'Sum: $\sum_[1]=1}^n [2]^2$', fontsize=18, ha='center')
plt.axis('off')
plt.show()

Drag options to blanks, or click blank then click option'

Ai

Bj

Ck

Dn

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables for the index and the squared term.

Using n as the index variable instead of the upper limit.

Choosing uncommon index letters like k or j.

The sum index is usually i, and the expression sums i squared from 1 to n.

5fill in blank

hard

Fill all three blanks to create a LaTeX expression for the binomial coefficient in the plot title.

Matplotlib

import matplotlib.pyplot as plt
plt.title(r'Binomial coefficient: $\binom[1][2] = \frac[3]!}}{{k! (n-k)!}}$')
plt.show()

Drag options to blanks, or click blank then click option'

An

Bk

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping n and k in the binomial coefficient.

Using k! in numerator instead of n!.

Forgetting to match the factorial variable with the binomial coefficient top.

The binomial coefficient is \binom{n}{k} = \frac{n!}{k! (n-k)!}.

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