plot() function basics in MATLAB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic purpose of the plot() function in MATLAB?

The plot() function is used to create 2D line plots to visualize data points connected by lines.

beginner

How do you plot the points (1,2), (2,4), and (3,6) using plot()?

Use plot([1 2 3], [2 4 6]) to plot x-coordinates [1 2 3] against y-coordinates [2 4 6].

intermediate

What does the command plot(x, y, 'r--') do?

It plots the data points with a red dashed line connecting them. 'r' means red color, '--' means dashed line style.

beginner

How can you add labels to the x-axis and y-axis in a plot?

Use xlabel('label') and ylabel('label') to add text labels to the x-axis and y-axis respectively.

intermediate

What happens if you call plot() multiple times without hold on?

Each new plot() call clears the previous plot, so only the last plot is visible unless you use hold on.

Which command plots a blue solid line connecting points (1,1), (2,4), and (3,9)?

A plot([1 2 3], [1 4 9], 'k.')

B plot([1 2 3], [1 4 9], 'r--')

C plot([1 2 3], [1 4 9], 'b-')

D plot([1 2 3], [1 4 9], 'g:')

The 'b-' option means blue solid line. Other options specify different colors or line styles.

What does plot(x, y) do if x is omitted and only plot(y) is called?

A Plots y against its index values starting at 1

B Throws an error

C Plots y against zeros

D Plots y against random values

If only y is given, MATLAB plots y values against their indices (1, 2, 3, ...).

How do you keep multiple plots visible on the same figure?

A Use <code>hold on</code>

B Use <code>hold off</code>

C Call <code>plot()</code> multiple times without any command

D Use <code>clear</code>

hold on keeps the current plot so new plots add to it instead of replacing.

Which command adds a title to a plot?

A xlabel('My Plot')

B legend('My Plot')

C ylabel('My Plot')

D title('My Plot')

title() adds a title above the plot.

What is the output of plot([1 2 3], [4 5 6], 'ko')?

A Red dashed line connecting points

B Black circle markers at points without connecting lines

C Black solid line connecting points

D Blue dotted line connecting points

'k' means black color, 'o' means circle markers, no line style means no connecting lines.

Explain how to create a simple 2D line plot in MATLAB using the plot() function.

Think about how you give x and y points to <code>plot()</code>.

Describe how to customize the color and style of a plot line using the plot() function.

Use a string like 'r--' to set red dashed lines.