Class 12 Maths

Matrices

NCERT Solution

Exercise 1 Part 1

Question 1: In the matrix write:

(i) The order of the matrix,

(ii) The number of elements,

(iii) Write the elements a13, a21, a33, a24, a23.

Solution:

(i) Since, the given matrix A has three rows and four columns, thus, order of the matrix = 3 x 4

(ii) The given matrix A has 3 x 4 = 12 elements

(iii) a13 = 19, a21 = 35, a33 = –5, a24 = 12, a23 = 5/2.

Question -2 – If a matrix has 24 elements, what are the possible orders it can have? What if it has 13 elements.

Solution: Since, a matrix is of order m x n has mn elements, thus, possible orders of the having 24 elements will be 1 x 24, 2 x 12, 3 x 8, 4 x 6, 6 x 4, 8 x 3, 12 x 2 and 24 x 1.

Matrix having 13 elements has possible orders are 1 x 13 and 13 x 1

Question: 3 – If a matrix has 18 elements, what are the possible orders it can have? What, if it has 5 elements?

Solution: Possible orders of matrix having 18 elements are 1 x 18, 2 x 9, 3 x 6, 6 x 3, 9 x 2, 18 x 1.

Similarly, possible orders of a matrix having 5 elements are 1 x 5 and 5 x 1

Question 4: Construct a whose elements are given by: Solution:    Exercise 3.1

Exercise 3.2