Question

To check the rank of a non-singular square matrix, we have to use ___________

(a) not required

(b) rankm()

(c) rankmatr()

(d) rank()

This question was posed to me in final exam.

This interesting question is from Linear Systems in section Beyond the Basics of MATLAB

Answer 1

Right answer is (d) rank()

To explain: Since the matrix is non-singular, the rank is the highest number of rows or columns (both are the same for a square matrix. Since we know the matrix is non-singular, we don’t have to use any command. We can directly say the rank is equal to the order of the matrix. If the matrix is not singular, we will have to use rank() to get a value of the rank.