Line styles, markers, and colors in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to plot a red dashed line.

MATLAB

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

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

A'b-.'

B'r--'

C'g:'

D'k-'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a color without a line style, like 'r' only.

Using a line style without a color, like '--' only.

The code uses 'r--' to plot a red dashed line in MATLAB.

2fill in blank

medium

Complete the code to plot blue circle markers connected by a solid line.

MATLAB

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

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

A'bo-'

B'g*--'

C'k:+'

D'ro-'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ro-' which is red circles instead of blue.

Using line styles like '--' which is dashed, not solid.

'bo-' means blue circle markers connected by a solid line.

3fill in blank

hard

Fix the error in the code to plot green star markers with dotted lines.

MATLAB

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

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

A'g:o'

B'g*-'

C'g-:'

D'g*:'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'g*-' which is solid line, not dotted.

Using 'g-:' which places line style before marker, incorrect order.

'g*:' correctly specifies green star markers with dotted lines.

4fill in blank

hard

Fill both blanks to plot magenta plus markers with dash-dot lines.

MATLAB

plot(x, y, '[1][2]')

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

A'm+'

B'+-'

C'-.'

D'o'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'o' instead of '+' for markers.

Mixing up line style symbols like '--' instead of '-.'.

'm+' specifies magenta color and plus markers, '-.' is dash-dot line style.

5fill in blank

hard

Fill all three blanks to plot black square markers with dotted lines and label the plot.

MATLAB

plot(x, y, '[1][2]');
title('[3]');

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

A'k'

B's:'

C'.'

D'My Plot'

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.' which is point marker instead of 's:' for square markers with dotted lines.

Forgetting to put the title string in quotes.

'k' is black color, 's:' is square marker with dotted lines, and the title is set to 'My Plot'.

Practice

1. Which of the following is the correct way to plot a red dashed line with circle markers in MATLAB?

easy

A. plot(x, y, 'ro-')

B. plot(x, y, '-ro')

C. plot(x, y, 'o-r')

D. plot(x, y, 'r--o')

Solution

1. Step 1: Understand MATLAB line style syntax

   In MATLAB, the format 'color lineStyle marker' is used inside the plot command, for example 'r--o' means red color, dashed line, and circle markers.

2. Step 2: Match the correct order

   The correct order is color first ('r'), then line style ('--'), then marker ('o'). So 'r--o' is correct.

3. Final Answer:

   plot(x, y, 'r--o') -> Option D

4. Quick Check:

   Color + line style + marker = 'r--o' [OK]

Hint: Remember order: color, line style, then marker [OK]

Common Mistakes:

• Putting marker before line style
• Using wrong order of characters
• Confusing color codes with markers

2. Which of the following MATLAB plot commands will produce a blue solid line with square markers?

easy

A. plot(x, y, 'b-s')

B. plot(x, y, 'sb:')

C. plot(x, y, 'b:sq')

D. plot(x, y, 'bs:')

Solution

1. Step 1: Identify the correct syntax for blue solid line with square markers

   In MATLAB, 'b' means blue, '-' means solid line, and 's' means square marker. The order is color, line style, marker.

2. Step 2: Check each option

   plot(x, y, 'b-s') 'b-s' correctly follows the order: blue color, solid line, square marker.

3. Final Answer:

   plot(x, y, 'b-s') -> Option A

4. Quick Check:

   Color + line style + marker = 'b-s' [OK]

Hint: Use 'color-lineStyle-marker' order in plot string [OK]

Common Mistakes:

• Mixing order of marker and line style
• Using invalid marker codes
• Adding extra characters like 'sq'

3. What will be the color and style of the line plotted by this command?

plot(x, y, 'g:*')

medium

A. Green dotted line with star markers

B. Green solid line with star markers

C. Green dash-dot line with star markers

D. Green dashed line with star markers

Solution

1. Step 1: Decode the plot style string 'g:*'

   'g' means green color, ':' means dotted line style, and '*' means star markers.

2. Step 2: Combine the meanings

   The line will be green, dotted, with star markers.

3. Final Answer:

   Green dotted line with star markers -> Option A

4. Quick Check:

   Color = green, line style = dotted, marker = star [OK]

Hint: ':' means dotted line, '*' means star marker [OK]

Common Mistakes:

• Confusing ':' with dash-dot line
• Mixing marker and line style symbols
• Assuming solid line by default

4. Identify the error in this MATLAB plot command:

plot(x, y, 'r--x-o')

medium

A. Color code 'r' is incorrect

B. Multiple markers specified, which is invalid

C. Line style '--' cannot be combined with markers

D. Missing semicolon at the end

Solution

1. Step 1: Analyze the plot style string 'r--x-o'

   This string tries to specify two markers: 'x' and 'o', which is not allowed in MATLAB plot format.

2. Step 2: Understand MATLAB plot style rules

   Only one marker can be specified along with one line style and one color. Multiple markers are invalid.

3. Final Answer:

   Multiple markers specified, which is invalid -> Option B

4. Quick Check:

   Only one marker allowed in plot style [OK]

Hint: Use only one marker symbol in plot style string [OK]

Common Mistakes:

• Adding multiple markers in one style string
• Ignoring MATLAB plot style syntax rules
• Thinking semicolon affects plot style

5. You want to plot two lines on the same graph: one with a green dash-dot line and circle markers, and the other with a magenta dotted line and square markers. Which MATLAB code correctly does this?

hard

A. plot(x1, y1, 'g-.o'); plot(x2, y2, 'm:s');

B. plot(x1, y1, 'g-o.'); hold on; plot(x2, y2, 'm.s:'); hold off;

C. plot(x1, y1, 'g-.o'); hold on; plot(x2, y2, 'm:s'); hold off;

D. plot(x1, y1, 'g:o-'); hold on; plot(x2, y2, 'm-s.'); hold off;

Solution

1. Step 1: Understand the required styles

   First line: green ('g'), dash-dot ('-.'), circle marker ('o'). Second line: magenta ('m'), dotted (':'), square marker ('s').

2. Step 2: Check each option for correct syntax and use of 'hold on'

   plot(x1, y1, 'g-.o'); hold on; plot(x2, y2, 'm:s'); hold off; uses 'g-.o' and 'm:s' correctly and uses 'hold on' to plot both lines on the same graph.

3. Step 3: Verify other options

   plot(x1, y1, 'g-o.'); hold on; plot(x2, y2, 'm.s:'); hold off; and D have incorrect order or invalid style strings. plot(x1, y1, 'g-.o'); plot(x2, y2, 'm:s'); misses 'hold on' so second plot overwrites first.

4. Final Answer:

   plot(x1, y1, 'g-.o'); hold on; plot(x2, y2, 'm:s'); hold off; -> Option C

5. Quick Check:

   Use correct style strings and 'hold on' to combine plots [OK]

Hint: Use 'hold on' to plot multiple lines with different styles [OK]

Common Mistakes:

• Forgetting 'hold on' to keep previous plots
• Mixing order of line style and marker
• Using invalid style strings like 'g:o-'