FREE MATLAB Matrix and Vector Operations Questions and Answers

Question 1

Given two matrices, A = [1 2; 3 4] and B = [5 6; 7 8], which of the following MATLAB commands will produce a matrix C where each element is the product of the corresponding elements in A and B (i.e., C(1,1) = A(1,1)*B(1,1), C(1,2) = A(1,2)*B(1,2), etc.)?

Accepted Answer

C = A .* B

Answer

C = A * B

Answer

C = A x B

Answer

C = matrix_multiply(A, B)

Question 2

A user defines a matrix M = [10 20 30; 40 50 60; 70 80 90]. Which command will extract the entire second row of M?

Accepted Answer

M(2, :)

Answer

M(2)

Answer

M(:, 2, :)

Answer

M(row=2)

Question 3

You have two vectors, V1 = [1; 2; 3] and V2 = [4; 5; 6]. You need to calculate the scalar dot product. Which of the following commands is the standard and most direct way to achieve this in MATLAB?

Accepted Answer

dot(V1, V2)

Answer

V1' * V2

Answer

V1 .* V2

Answer

cross(V1, V2)

Question 4

Consider the command `C = [A; B]`. What condition must matrices A and B satisfy for this command to execute without error?

Accepted Answer

A and B must have the same number of columns.

Answer

A and B must have the same number of rows.

Answer

A and B must be square matrices.

Answer

A and B must have the same number of total elements.

Question 5

Given a vector `V = [5, 12, 3, 18, 9, 15]`, which of the following commands will return a logical vector indicating which elements of V are greater than 10?

Accepted Answer

V > 10

Answer

find(V > 10)

Answer

V(V > 10)

Answer

select(V > 10)

Question 6

What is the result of the expression `[1 2 3] * [4; 5; 6]` in MATLAB?

Accepted Answer

The scalar value 32.

Answer

An error, because the matrix dimensions do not agree.

Answer

The vector [4 10 18].

Answer

The matrix [4 5 6; 8 10 12; 12 15 18].

MATLAB FREE MATLAB Matrix and Vector Operations Questions and Answers

Given two matrices, A = [1 2; 3 4] and B = [5 6; 7 8], which of the following MATLAB commands will produce a matrix C where each element is the product of the corresponding elements in A and B (i.e., C(1,1) = A(1,1)B(1,1), C(1,2) = A(1,2)B(1,2), etc.)?