Labels, title, and legend in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a title to the plot.

MATLAB

plot(x, y)
title([1])

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

AMy Plot

Btitle

C"My Plot"

Dxlabel

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the title text in quotes.

Using xlabel instead of title.

The title function requires the title text as a string, so it must be in quotes.

2fill in blank

medium

Complete the code to label the x-axis.

MATLAB

plot(x, y)
xlabel([1])

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

A"Time (s)"

BTime (s)

Cx-axis

Dxlabel

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around the label text.

Passing a variable name instead of a string.

The xlabel function needs the label as a string, so it must be in quotes.

3fill in blank

hard

Fix the error in the code to add a legend.

MATLAB

plot(x, y1, x, y2)
legend([1])

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

A["Data1", "Data2"]

B{"Data1", "Data2"}

C'Data1', 'Data2'

D"Data1", "Data2"

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets instead of curly braces.

Passing a single string with commas instead of a cell array.

The legend function expects a cell array of strings, which in MATLAB is created with curly braces {}.

4fill in blank

hard

Fill both blanks to add labels and a title to the plot.

MATLAB

plot(x, y)
xlabel([1])
title([2])

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

A"Time (s)"

BTime (s)

C"Sample Data"

DSample Data

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes for the labels.

Swapping xlabel and title.

Both xlabel and title require string inputs, so the labels must be in quotes.

5fill in blank

hard

Fill all three blanks to add labels, title, and legend to the plot.

MATLAB

plot(x, y1, x, y2)
xlabel([1])
title([2])
legend([3])

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

A"Time (s)"

B"Experiment Results"

C{"Trial 1", "Trial 2"}

D["Trial 1", "Trial 2"]

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets for legend labels.

Not quoting xlabel or title text.

xlabel and title require strings in quotes, and legend requires a cell array of strings using curly braces.

Practice

1. Which MATLAB function is used to add a label to the x-axis of a plot?

easy

A. xlabel

B. ylabel

C. title

D. legend

Solution

1. Step 1: Understand axis labeling functions

   In MATLAB, xlabel labels the x-axis, ylabel labels the y-axis, title adds a main heading, and legend explains plot lines.

2. Step 2: Identify the function for x-axis label

   The function xlabel is specifically designed to add a label to the x-axis.

3. Final Answer:

   xlabel -> Option A

4. Quick Check:

   Label x-axis = xlabel [OK]

Hint: Use xlabel for x-axis label, ylabel for y-axis [OK]

Common Mistakes:

• Confusing xlabel with ylabel
• Using title instead of axis labels
• Using legend for axis labels

2. Which of the following is the correct syntax to add a legend to a plot with two lines labeled 'Data1' and 'Data2'?

easy

A. legend{'Data1', 'Data2'}

B. legend = ('Data1', 'Data2')

C. legend['Data1', 'Data2']

D. legend('Data1', 'Data2')

Solution

1. Step 1: Recall correct legend syntax

   In MATLAB, the function legend is called with parentheses and string arguments to label plot lines.

2. Step 2: Identify correct syntax

   The correct syntax uses parentheses and comma-separated strings: legend('Data1', 'Data2'). Other options use invalid assignment or brackets.

3. Final Answer:

   legend('Data1', 'Data2') -> Option D

4. Quick Check:

   legend('labels') uses parentheses [OK]

Hint: Use legend('label1', 'label2') with parentheses [OK]

Common Mistakes:

• Using assignment '=' instead of function call
• Using square or curly brackets
• Missing quotes around labels

3. What will be the title of the plot after running this MATLAB code?

plot(1:5, [2 4 6 8 10]);
title('Sales Over Time');

medium

A. plot(1:5, [2 4 6 8 10])

B. Sales Over Time

C. 1:5

D. No title

Solution

1. Step 1: Understand the title function

   The title function sets the main heading of the plot to the given string.

2. Step 2: Check the given code

   The code calls title('Sales Over Time'), so the plot's title will be exactly 'Sales Over Time'.

3. Final Answer:

   Sales Over Time -> Option B

4. Quick Check:

   title('text') sets plot title [OK]

Hint: title('text') sets the plot's main heading [OK]

Common Mistakes:

• Confusing title with axis labels
• Expecting variable values as title
• No title if title function missing

4. Identify the error in this MATLAB code snippet:

plot(x, y);
xlabel = 'Time';
ylabel('Value');
legend('Line1');

medium

A. Using assignment '=' with xlabel instead of function call

B. Missing ylabel function call

C. legend syntax is incorrect

D. plot function is missing arguments

Solution

1. Step 1: Check xlabel usage

   The code uses xlabel = 'Time'; which assigns a string to variable xlabel instead of calling the function xlabel('Time').

2. Step 2: Verify other lines

   ylabel('Value') and legend('Line1') are correctly called as functions. The plot function has arguments x, y assumed defined.

3. Final Answer:

   Using assignment '=' with xlabel instead of function call -> Option A

4. Quick Check:

   Use xlabel('text'), not xlabel = 'text' [OK]

Hint: Call xlabel as function: xlabel('text'), not assignment [OK]

Common Mistakes:

• Assigning xlabel instead of calling function
• Confusing ylabel syntax
• Incorrect legend usage

5. You have plotted two data sets on the same graph using:

plot(x, y1, '-r', x, y2, '-b');

How do you add a title 'Comparison', label the x-axis as 'Time', the y-axis as 'Value', and add a legend with labels 'Data1' and 'Data2'?

hard

A. title = 'Comparison'; xlabel = 'Time'; ylabel = 'Value'; legend = ('Data1', 'Data2');

B. title('Comparison'); xlabel('Time'); ylabel('Value'); legend(['Data1', 'Data2']);

C. title('Comparison'); xlabel('Time'); ylabel('Value'); legend('Data1', 'Data2');

D. title('Comparison'); xlabel('Time'); ylabel('Value'); legend{'Data1', 'Data2'};

Solution

1. Step 1: Use correct function calls for labels and title

   Functions title, xlabel, and ylabel require parentheses with string arguments.

2. Step 2: Use correct legend syntax

   The legend function takes comma-separated strings inside parentheses, not assignment or brackets.

3. Final Answer:

   title('Comparison'); xlabel('Time'); ylabel('Value'); legend('Data1', 'Data2'); -> Option C

4. Quick Check:

   Use function calls with parentheses for labels and legend [OK]

Hint: Use function calls with parentheses for all labels and legend [OK]

Common Mistakes:

• Assigning strings instead of calling functions
• Using brackets or braces for legend
• Missing quotes around labels