Answer:

. In the matrix A = , WRITE:

(i) The order of the matrix.

(ii) The number of elements.

(iii) Write the elements

Ans. (i) There are 3 horizontal lines (rows) and 4 vertical lines (columns) in the GIVEN matrix A.

Therefore, Order of the matrix is 3 x 4.

(ii) The number of elements in the matrix A is 3 x 4 = 12.

(iii) Element in first row and third column = 19

Element in second row and first column = 35

Element in third row and third column =

Element in second row and fourth column = 12

Element in second row and third column =

NCERT Solutions class 12 Maths Exercise 3.1

2. If a matrix has 24 elements, what are possible orders it can order? What, if it has 13 elements?

Ans. Since, a matrix having element is of order

(i) Therefore, there are 8 possible matrices having 24 elements of orders 1 x 24, 2 x 12, 3 x 8, 4 x 6, 24 x 1, 12 x 2, 8 x 3, 6 x 4.

(ii) Prime number 13 = 1 x 13 and 13 x 1

Therefore, there are 2 possible matrices of order 1 x 13 (Row matrix) and 13 x 1 (Column matrix).

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

Ans. Since, a matrix having element is of order

(i) Therefore, there are 6 possible matrices having 18 elements of orders 1 x 18, 2 x 9, 3 x 6, 18 x 1, 9 x 2, 6 x 3.

(ii) Prime number 5 = 1 x 5 and 5 x 1

Therefore, there are 2 possible matrices of order 1 x 5 (Row matrix) and 5 x 1 (Column matrix).

NCERT Solutions class 12 Maths Exercise 3.1

4. Construct a 2 x 2 matrix A = whose elements are given by:

(i)

(ii)

(iii)

Ans. (i) Given: ……….(i)

Putting in EQ. (i)

Putting in eq. (i)

Putting in eq. (i)

Putting in eq. (i)

A2 x 2 =

(ii) Given: ……….(i)

Putting in eq. (i)

Putting in eq. (i)

Putting in eq. (i)

Putting in eq. (i)

A2 x 2 =

(iii) Given: ……….(i)

Putting in eq. (i)

Putting in eq. (i)

Putting in eq. (i)

Putting in eq. (i)

A2 x 2 =