MATLAB Matrix and Vector Operations 5

Question 1

What does `A(end, :)` return for a matrix A?

Accepted Answer

The last row of A

Answer

The colon : selects all columns, and end refers to the last row index, returning the entire last row.

Question 2

How do you horizontally concatenate two matrices A and B with the same number of rows in MATLAB?

Accepted Answer

[A, B]

Answer

[A, B] or [A B] concatenates A and B side by side, requiring equal row counts; equivalently horzcat(A,B).

Question 3

What does `trace(A)` return for a matrix A?

Accepted Answer

The sum of diagonal elements

Answer

trace returns the sum of the main diagonal elements of a square matrix.

Question 4

What is the result of `[1 2 3] > 2` in MATLAB?

Accepted Answer

Both B and C are correct

Answer

MATLAB returns a logical array [0 0 1] (equivalently [false false true]) where the condition is satisfied.

Question 5

Which MATLAB function sorts a matrix A along its columns in ascending order?

Accepted Answer

Both A and B

Answer

sort(A) and sort(A, 1) both sort each column independently in ascending order (dimension 1 = along rows).

MATLAB - MATLAB Technical Computing Practice Test