Question

The order of a matrix [2 5 7] is

Answer 1

The order of a matrix is denoted by writing it as the product of number of rows and number of columns.
The order of a matrix is needed to undertake various operations with matrices. Different operations that can be undertaken with matrices are – Addition, Subtraction, Multiplication and Division.

Complete step by step solution:
A matrix is a set of ab numbers (real as well as imaginary) arranged in the form of a rectangular array of a rows and b columns. The matrix formed by a combination of a rows and b columns is a × b matrix.
The order of the matrix is determined by determining the number of rows and number of columns.
Rows are horizontal in nature while columns are vertical in nature.
The number of rows in the matrix, $[2\text{ }5\text{ }7]$ is $1$ as there is one horizontal line in matrix while number of columns in given matrix are $3$ as there are three vertical entries in three vertical lines. This makes the order of the matrix equal to $1\times 3$.

Additional information:
Matrices can be square matrices (matrices with equal number of rows and columns) or rectangular matrices (unequal number of rows and columns). Diagonal matrix is one in which all entries apart from those on diagonal are zero.
Triangular matrices are one in which all entries below diagonal are zero (upper triangular matrix) or all entries above diagonal are zero (lower triangular matrix).

Note:

The order of the matrix should be the same to add or subtract two or more matrices.
To multiply two matrices, the number of columns of one matrix should be equal to the number of rows of another matrix involved in multiplication.