MATLAB Matrix and Vector Operations 3

Question 1

What does `norm(v, Inf)` compute for a vector v in MATLAB?

Accepted Answer

The maximum absolute value of any element

Answer

The infinity norm of a vector is the maximum of the absolute values of its elements.

Question 2

Given A is a 3x4 matrix, what is the size of `A' * A`?

Accepted Answer

4x4

Answer

A' is 4x3, so A'*A is (4x3)*(3x4) = 4x4.

Question 3

Which MATLAB function performs LU decomposition of matrix A?

Accepted Answer

lu(A)

Answer

lu(A) returns lower and upper triangular factors L and U such that A = L*U (with optional permutation).

Question 4

What does `cross([1 0 0], [0 1 0])` return in MATLAB?

Accepted Answer

[0 0 1]

Answer

The cross product of unit vectors i and j equals unit vector k, which is [0 0 1].

Question 5

How do you compute the cumulative sum of a vector v in MATLAB?

Accepted Answer

cumsum(v)

Answer

cumsum returns a vector where each element is the sum of all previous elements including itself.

MATLAB - MATLAB Technical Computing Practice Test