**Table of content**

**NCERT Solutions for Class 12 Maths Chapter 3 Matrices**

NCERT Solutions for Class 12 Maths Chapter 3 will strengthen student’s basic and conceptual fundamentals to score better marks and stay ahead. Our Mathematics experts who constantly work hard and keep detailed eyes on the subject have prepared these NCERT solutions.

NCERT Solutions for Class 12 Maths Chapter 3 Matrices is extremely helpful in revising complete syllabus and getting a strong base. NCERT solutions for Matrices Class 12 Maths give step by step solution for each and every question of the chapter. These solutions will also help you with your homework.

Our team of expert teachers has created NCERT solutions for class 12 Maths Chapter 3 Matrices according to curriculum and pattern of syllabus. Our app will help you to get complete NCERT solutions.

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**CBSE Class 12 Maths Chapter 3 – Matrices NCERT Solutions**

NCERT solutions for class 12 Maths Chapter 3 Matrices help students to understand matrices in an easy and self-explanatory way. The conceptual background of matrices is necessary for various branches of mathematics. Matrices are one of the most useful tools in mathematics as well as other areas of science like cryptography, genetics, economics, sociology, modern psychology and industrial management, etc.

**Sub-topics covered under NCERT Solutions for Class 12 Maths Chapter 3**

- 3.1 Introduction
- 3.2 Matrix
- 3.2.1 Order of Matrix

- 3.3 Types of Matrices
- 3.4 Operations on Matrices
- 3.4.1 Addition of matrices
- 3.4.2 Multiplication of a matrix by a scalar
- 3.4.3 Properties of matrix addition
- 3.4.4 Properties of scalar multiplication of a matrix
- 3.4.5 Multiplication of matrices
- 3.4.6 Properties of multiplication of matrices

- 3.5 Transpose of a Matrix
- 3.5.1 Properties of the transpose of the matrices

- 3.6 Symmetric and Skew-Symmetric Matrices
- 3.7 Elementary Operation (Transformation) of a Matrix
- 3.8 Invertible Matrices
- 3.8.1 Inverse of a matrix by elementary operations

**NCERT Solutions for Class 12 Maths Chapter 3**

Matrices deals with arranging and organizing them in a proper form of a table. In our NCERT Solutions for Class 12 Maths Chapter 3, students will also learn about various ways to apply matrices with determinants. This chapter covers all aspects of matrices with their types, operations, and applications.

Let us discuss the sub-topics in detail.

**3.1 Introduction**

It simplifies our work to a great extent when compared with other straight forward methods. Matrices are not only used as a representation of the coefficients in the system of linear equations but also used in a personal computer.

**3.2 Matrix**

A matrix is an ordered rectangular collection of numbers or functions. These numbers are called the elements or the entries of the matrix. It contains some Rows and Columns.

**3.2.1 Order of Matrix**

Each matrix has m rows and n columns. Its order is m × n and we read it as an m by n matrix.

**3.3 Types of Matrices**

This topic discusses various types of Matrices as Column Matrix, Row Matrix, Square Matrix, Identity Matrix, etc.

**3.4 Operations on Matrices**

It introduces some basic but important operations on matrices, like the addition of matrices, multiplication of a matrix by a scalar, difference, and multiplication of matrices, etc. Also, it explains various properties of matrices based on these operations.

**3.4.1 Addition of Matrices**

It elaborates the process to add two matrices.

**3.4.2 Multiplication of a matrix by a scalar**

It elaborates the process to multiply a matrix by a scalar quantity.

**3.4.3 Properties of matrix addition**

It shows some additive properties of matrices.

**3.4.4 Properties of scalar multiplication of a matrix**

It shows some multiplicative properties of matrices.

**3.4.5 Multiplication of matrices**

It elaborates the process to multiply two matrices.

**3.4.6 Properties of multiplication of matrices**

It shows some multiplicative properties of matrices.

**3.5 Transpose of a Matrix**

It explains the meaning and procedure of finding the transpose of a matrix. It plays the main role to define and find the symmetric and skew-symmetric matrices.

**3.5.1 Properties of the transpose of the matrices**

It explains some properties of the transpose of matrices.

**3.6 Symmetric and Skew-Symmetric Matrices**

It defines two more types of matrices which used to get some interesting results.

**3.7 Elementary Operation (Transformation) of a Matrix**

It explores the elementary transformations of the matrices. There are six transformations possible on a matrix, three of which are due to rows and three due to columns.

**3.8 Invertible Matrices**

It defines the existence of inverse of a matrix. This inverse matrix exists and gives the identity matrix after multiplying it with the original matrix, if it exists, it will be unique.

**3.8.1 Inverse of a matrix by elementary operations**

It discusses the elementary operations on the inverse of a matrix.

**You can download NCERT Solutions for Class 12 Maths Chapter 3 PDF by clicking on the download button below**

### Solved Questions for You

**Question 1: Matrices A and B will be inverse of each other only if**

*AB*=*BA**AB*=0,*BA*=*I**AB*=*BA*=0*AB*=*BA*=*I*

**Answer: **We know that if *A* is a square of order *m*, and if there exists another square matrix *B* of the same order *m*, such that *AB*=*I*, then *B* is said to be the inverse of *A*.

In this case, it is clear that *A* is the inverse of *B*.

Thus , matrices *A* and *B* will be inverses of each other only if *AB*=*BA*=*I*.

**Question 2: If a matrix has 24 elements, what are the possible order it can have? What, if it has 13 elements?**

**Answer: **We know that if a matrix is of the order *m*×*n*, it has *mn* elements.

Thus to find all the possible orders of a matrix having 24 elements, we have to find all the ordered pairs of natural numbers whose product is 24.

The ordered pairs are(1,24),(24,1),(2,12),(12,2),(3,8),(8,3),(4,6) and (6,4)

Hence, the possible orders of a matrix having 24 elements are:

1×24,24×1,2×12,12×2,3×8,8×3,4×6,6×4

(1,13) and (13,1) are the ordered pairs of natural numbers whose product is 13.

Hence, the possible orders of a matrix having 13 elements are 1×13 and 13×1

**Question 3: If n=p, then the order of the matrix 7X−5Z is: **

*p*×2**2×***n**n*×3*p*×*n*

**Answer: **In this, order of *X*=2×*n*

and order of *Z*=2×*p*

Therefore, *n*=*p*

Hence order of 7*X*−5*Z*=2×*n*.

Thus option (B) is correct.

**Question 4: If A,B are symmetric matrices of same order, then AB−BA is a ,**

A. Skew symmetric matrix

**Symmetric matrix****Zero matrix****Identity matrix**

**Answer: ** Given, *A* and *B* are symmetric matrices, therefore, we have:*A*′=*A* and *B*′=*B*……….(*i*)

Consider

(*AB*−*BA*)′=(*AB*)′−(*BA*)′,[∵(*A*−*B*)′=*A*′−*B*′]

=*B*′*A*′−*A*′*B*′,[∵(*AB*)′=*B*′*A*′]

=*BA*−*AB* [by (i) ]

=−(*AB*−*BA*)

∴(*AB*−*BA*)′=−(*AB*−*BA*)

Thus, (*AB*−*BA*) is a skew-symmetric matrix.

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