Row and column vectors in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a row vector with elements 1 to 5.

MATLAB

v = [1 [1] 5];

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

A:

B;

C,

D.

Attempts:

3 left

💡 Hint

Common Mistakes

Using a semicolon ; inside square brackets creates a column vector, not a row vector.

Using a comma , is valid but not the best way to create a sequence.

In MATLAB, the colon operator : creates a sequence of numbers. So 1:5 creates a row vector [1 2 3 4 5].

2fill in blank

medium

Complete the code to create a column vector with elements 1 to 5.

MATLAB

v = [1[1]5]';

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

A.

B:

C,

D;

Attempts:

3 left

💡 Hint

Common Mistakes

Using a semicolon ; creates [1;5]' which is row [1 5].

Using a comma , creates [1,5]' which is column [1;5] but only two elements.

In MATLAB, the colon operator : creates the row vector [1 2 3 4 5]. Transposing it with ' creates the column vector [1;2;3;4;5].

3fill in blank

hard

Fix the error in the code to create a column vector with elements 1 to 3.

MATLAB

v = [1 [1] 3]';

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

A:

B,

C;

D.

Attempts:

3 left

💡 Hint

Common Mistakes

Using a semicolon ; creates [1;3]' row [1 3].

Using a comma , creates [1,3]' column [1;3] only two elements.

In MATLAB, use colon : to create row vector [1 2 3], then transpose ' to get column vector [1;2;3].

4fill in blank

hard

Complete the code to create a row vector with elements 2 to 8.

MATLAB

v = [[1] : 8];

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

A2

B:

C,

D;

Attempts:

3 left

💡 Hint

Common Mistakes

Using semicolon ; creates a column vector, not a row vector.

Using commas , without the colon operator does not create a sequence.

In MATLAB, the colon operator : creates sequences.

5fill in blank

hard

Complete the code to create a column vector with elements 5 to 15.

MATLAB

v = [[1]:15]';

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

A5

B:

C;

D,

Attempts:

3 left

💡 Hint

Common Mistakes

Using commas , creates a row vector before transpose.

Not using the colon operator fails to create the full sequence.

Practice

1. Which of the following correctly creates a row vector in MATLAB?

easy

A. v = (1, 2, 3, 4);

B. v = [1 2 3 4];

C. v = [1; 2; 3; 4];

D. v = {1 2 3 4};

Solution

1. Step 1: Understand row vector syntax

   Row vectors use square brackets with spaces or commas between elements.

2. Step 2: Identify correct option

   v = [1 2 3 4]; uses spaces inside square brackets, which is correct for a row vector.

3. Final Answer:

   v = [1 2 3 4]; -> Option B

4. Quick Check:

   Row vector = horizontal elements in [ ] [OK]

Hint: Row vectors use spaces or commas inside [ ] [OK]

Common Mistakes:

• Using semicolons creates a column vector, not a row vector
• Using parentheses instead of square brackets
• Using curly braces creates a cell array, not a vector

2. Which of the following is the correct syntax to create a column vector with elements 5, 6, and 7 in MATLAB?

easy

A. v = [5 6 7];

B. v = (5; 6; 7);

C. v = [5; 6; 7];

D. v = {5; 6; 7};

Solution

1. Step 1: Recall column vector syntax

   Column vectors use square brackets with semicolons separating elements vertically.

2. Step 2: Find the option matching this syntax

   v = [5; 6; 7]; uses semicolons inside square brackets, which is correct for a column vector.

3. Final Answer:

   v = [5; 6; 7]; -> Option C

4. Quick Check:

   Column vector = vertical elements separated by ; [OK]

Hint: Use semicolons inside [ ] for column vectors [OK]

Common Mistakes:

• Using spaces instead of semicolons creates a row vector
• Using parentheses instead of square brackets
• Using curly braces creates a cell array, not a vector

3. What is the output of the following MATLAB code?

v = [10 20 30];
size_v = size(v);

medium

A. [1 1]

B. [3 1]

C. [3 3]

D. [1 3]

Solution

1. Step 1: Understand the vector shape

   v is defined with spaces inside [ ], so it is a row vector with 1 row and 3 columns.

2. Step 2: Apply size function

   size(v) returns the dimensions as [number_of_rows number_of_columns], which is [1 3].

3. Final Answer:

   [1 3] -> Option D

4. Quick Check:

   Row vector size = [1 number_of_elements] [OK]

Hint: Row vector size is 1 row and number of columns [OK]

Common Mistakes:

• Confusing row and column vector sizes
• Expecting size to return number of elements only
• Mixing up output format of size function

4. Identify the error in the following MATLAB code that tries to create a column vector:

v = [1, 2; 3, 4];

medium

A. The vector is actually a 2x2 matrix, not a column vector.

B. The commas should be replaced with semicolons.

C. Square brackets cannot be used for vectors.

D. The semicolon at the end is missing.

Solution

1. Step 1: Analyze the matrix dimensions

   The code uses commas and semicolons inside [ ], which creates a 2x2 matrix, not a column vector.

2. Step 2: Understand column vector requirements

   A column vector must have one column and multiple rows, but this code has 2 rows and 2 columns.

3. Final Answer:

   The vector is actually a 2x2 matrix, not a column vector. -> Option A

4. Quick Check:

   Mixed commas and semicolons create matrices, not vectors [OK]

Hint: Commas separate columns; semicolons separate rows [OK]

Common Mistakes:

• Thinking commas separate rows
• Assuming semicolons are optional for columns
• Confusing matrix with vector shapes

5. You want to create a 1x5 row vector with elements from 1 to 5, then convert it to a 5x1 column vector. Which MATLAB code correctly does this?

hard

A. rowVec = [1 2 3 4 5];
colVec = rowVec';

B. rowVec = [1; 2; 3; 4; 5];
colVec = rowVec;

C. rowVec = [1 2 3 4 5];
colVec = rowVec(:)';

D. rowVec = [1 2 3 4 5];
colVec = rowVec;

Solution

1. Step 1: Create a row vector

   rowVec = [1 2 3 4 5]; creates a 1x5 row vector using spaces inside square brackets.

2. Step 2: Convert row vector to column vector

   Using the transpose operator (') converts the row vector to a 5x1 column vector.

3. Final Answer:

   rowVec = [1 2 3 4 5]; colVec = rowVec'; -> Option A

4. Quick Check:

   Transpose operator ' flips row to column vector [OK]

Hint: Use ' (transpose) to switch row to column vector [OK]

Common Mistakes:

• Using semicolons inside row vector definition
• Forgetting to transpose to get column vector
• Assuming rowVec = colVec creates column vector