MATLAB Matrix and Array Operations 3

Question 1

What does `eye(4)` create in MATLAB?

Accepted Answer

A 4×4 identity matrix

Answer

`eye(n)` creates an n×n identity matrix with ones on the main diagonal and zeros elsewhere.

Question 2

What is the result of `reshape([1 2 3 4 5 6], 2, 3)` in MATLAB?

Accepted Answer

[1 3 5; 2 4 6]

Answer

MATLAB fills matrices column-by-column, so reshape fills column 1 with [1;2], column 2 with [3;4], column 3 with [5;6].

Question 3

What does the `diag(A)` function return when A is a square matrix?

Accepted Answer

A vector of A's main diagonal elements

Answer

When passed a matrix, `diag` extracts the main diagonal as a column vector.

Question 4

Which MATLAB function computes the determinant of a square matrix?

Accepted Answer

det(A)

Answer

`det(A)` computes the determinant of square matrix A.

Question 5

What does `A'` (apostrophe) do to a complex matrix A in MATLAB?

Accepted Answer

Returns the complex conjugate transpose (Hermitian)

Answer

The apostrophe `'` operator computes the complex conjugate transpose; for real matrices it is the same as a plain transpose.

MATLAB - MATLAB Technical Computing Practice Test