NCERT Solutions for Class 12 Maths Chapter 4 Determinants

NCERT Solutions for Class 12 Maths Chapter 4 – Free PDF Download

NCERT Solutions For Class 12 Maths Chapter 4 Determinants are available at BYJU’S which are given by our expert faculty. The step-by-step solutions for all the questions enlisted under the chapter, which is included in the CBSE syllabus 2023-24. Each solution has been explained using suitable examples or formulas. The NCERT Solutions for Class 12 Maths are written considering the marking scheme. BYJU’S aims to bring out the very best in students through additional skill-building exercises that are tailored to their grade levels, abilities and interests.

A determinant is a number that can be calculated for only square matrices. In solving a system of linear equations, a determinant plays an important role in checking whether the system of equations has a unique solution or not. It has many applications in science, engineering, social sciences, and economics, etc. The NCERT Solutions for Class 12 of this chapter cover all the problems, such as finding the determinant of a 2×2 matrix, or 3×3 matrix, evaluating the area of the triangle, and finding the equation of the line using determinant, minors, and co-factors. They also cover problems involving calculating the determinant using minor and co-factor, adjoint, and the inverse of a matrix. Students can now access the PDF of NCERT Solutions for Class 12 Maths Chapter 4 for free from the link given below.

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NCERT Solutions for Class 12 Maths Chapter 4 Determinants

Chapter Determinants has a total of 6 exercises and a miscellaneous exercise that covers all the questions related to the chapter. The topics discussed in Chapter 4 NCERT Solutions for Class 12 Maths include the following:

4.1 Introduction

Students have already read about how to represent a system of linear equations using matrices and the condition to know whether this system has a unique solution or not based on the determinant. These things will be revised under this section.

4.2 Determinant

4.2.1 Determinant of a matrix of order one

4.2.2 Determinant of a matrix of order two

4.2.3 Determinant of a matrix of order 3 × 3

In this section, students will learn how to find the determinant of a square matrix of different orders such as one, two and three, along with examples.

4.3 Properties of Determinants

In the previous section, students have learnt how to expand the determinants. In this section, they will study some properties of determinants which simplify their evaluation by obtaining the maximum number of zeros in a row or a column. These properties are correct for determinants of any order. However, in this chapter, it has been limited to determinants of order three only.

4.4 Area of a Triangle

We can find the area of a triangle using the formula when the coordinates of three vertices have been given. In this section, you will learn how to find the area of the triangle by converting the points into the form of a determinant.

4.5 Minors and Cofactors

Students will learn to write the expansion of a determinant in compact form using minors and cofactors after practising the problems in this section.

4.6 Adjoint and Inverse of a Matrix

4.6.1 Adjoint of a matrix

After solving the problems in this section, you will understand clearly how to find the inverse of a matrix using adjoint. Many theorems and examples are given in this section to enhance your skills.

4.7 Applications of Determinants and Matrices

4.7.1 Solution of a system of linear equations using the inverse of a matrix

Here, in these NCERT Solutions, you will get a complete description of applications of determinants and matrices for solving the system of linear equations in two or three variables and how to check the consistency of the system of linear equations.

Exercise 4.1 Solutions: 8 Questions (2 Long, 5 Short Answers, 1 MCQ)

Exercise 4.2 Solutions: 16 Questions(7 Long, 7 Short, 2 MCQs)

Exercise 4.3 Solutions: 5 Questions ( 4 Short Answers, 1 MCQ)

Exercise 4.4 Solutions: 5 Questions (4 Long, 1 MCQ)

Exercise 4.5 Solutions: 18 Questions (11 Long, 5 Short, 2 MCQs)

Exercise 4.6 Solutions: 16 Questions (13 Long, 3 Short)

Miscellaneous Exercise Solutions: 19 Questions (15 Long, 1 Short, 3 MCQs)

Key Features of NCERT Solutions for Class 12 Maths Chapter 4 Determinants

The NCERT Solutions Class 12 of BYJU’S for Chapter 4 cover the following points and formulas. 

• If any two rows or any two columns are identical or proportional, then the value of the determinant is zero
• A square matrix A has an inverse if and only if A is non-singular
• The unique solution of equation AX = B is given by X = A–1 B, where A ≠ 0
• If a system of equations is consistent, then it has a solution
• If a system of equations is inconsistent, then there is no solution
• For a square matrix A in matrix equation AX = B:

If | A| ≠ 0, then there exists a unique solution

If | A| = 0 and (adj A) B ≠ 0, then there exists no solution

If | A| = 0 and (adj A) B = 0, then system may or may not be consistent

Disclaimer – 

Dropped Topics – 4.3 Properties of Determinants, Page 137-143 Miscellaneous Examples 30–32 and 34 Ques. 2, 4–6, 11–15 and 17 (Miscellaneous Exercise), Page 144 Summary Points 4–11