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NCERT Solutions class 12 Mathematics I 3. Matrices Exercise 3.2

Detailed NCERT Solutions for 12 Mathematics I 3. Matrices to simplify learning. Understand chapters clearly and practice with free solutions for better results.

NCERT Solutions class 12 Mathematics I 3. Matrices Exercise 3.2

NCERT Solutions class 12 Mathematics I 3. Matrices Exercise 3.2

Detailed NCERT Solutions for 12 Mathematics I 3. Matrices to simplify learning. Understand chapters clearly and practice with free solutions for better results.

12 Mathematics I Chapter 3. Matrices - Exercise 3.2

Preparing for exams becomes easier with Exercise 3.2. Whether you are studying for board exams or mid-term exams, 12 Mathematics I Chapter 3. Matrices solutions provide quick revising points, well-structured answers, and additional practice material to help you score better.

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3. Matrices

Exercise 3.2


Exercise 3.2

Ques.1. Let A =  B =  C = . Find each of the following:

(i) A + B

(ii) A – B

(iii) 3A – C

(iv) AB

(v) BA

Ans. (i) A + B =  = 

(ii) A – B =  = 

(iii) 3A – C =  = 

(iv) AB =  = 

(v) BA =  = 

 

 

Ques.2. Compute the following:

(i) 

(ii)  

(iii) 

(iv)  

Ans. (i)   = 

(ii) 

(iii)   = 

(iv)  = 

 

 

Ques.3. Compute the indicated products:

(i) 

(ii)  

(iii) 

(iv)  

(v) 

(vi)  

Ans. (i)  = 

(ii)  = 

(iii)  = 

(iv) 

  = 

(v) 

(vi) 

 

 

Ques.4. If A =  B =  and C =  then compute (A + B) and (B – C). Also, verify that A + (B – C) = (A + B) – C.

Ans. A + B =  =  = 

B – C =  =  = 

Now, A + (B – C) = (A + B) – C

   = 

   = 

   = 

 L.H.S. = R.H.S. 

 hance Proved.

 

 

Ques.5. If A =  and B =  then compute 3A – 5B.

Ans. 3A – 5B = 

 

 

Ques.6. Simplify:  

Ans. Given: 

 

 

Ques.7. Find X and Y, if:

(i) X + Y =  and X – Y =  

(ii) 2X + 3Y =  and 3X + 2Y =  

Ans. (i) Given: X + Y =   …..(i)

and X – Y =   …..(ii)

Adding eq. (i) and (ii), we get

  2X = 

  X = 

Subtracting eq. (i) and (ii), we get

  2Y = 

  Y = 

(ii) Given: 2X + 3Y =   …..(i)

 and 3X + 2Y =   …..(ii)

Multiplying eq. (i) by 2, 4X + 6Y =     ……….(iii)

Multiplying eq. (ii) by 3, 9X + 6Y =    ………(iv)

subtracting Eq. (iii) from Eq. (iv)

5X = 

 X = 

Now, From eq. (i),  3Y =  2X = 

  3Y =  = 

  Y = 

 

 

Ques.8. Fin X if Y =  and 2X + Y =  

Ans. 2X + Y = 

 2X =  – Y

 2X = 

 2X = 

 X =  = 

 

 

Ques.9. Find  and  if  

Ans. Given: 

 

 

Equating corresponding entries, we have

 and 

  and 

  and 

  and 

 

 

Ques.10. Solve the equation for  and  if  

Ans. Given: 

 

 

Equating corresponding entries, we have

         

And          

And    

And          

 

 

Ques.11. If  find the values of  and  

Ans. Given: 

 

 

Equating corresponding entries, we have

 ……….(i) and   ……….(ii)

Adding eq. (i) and (ii), we have    

Putting  in eq. (ii),     

 

 

Ques.12. Given:  find the values of  and 

Ans. Given: 

 

Equating corresponding entries, we have

       

And 

 

 

 

And      ……….(i)

And     

Putting  in eq. (i),   

    

  

 

 

Ques.13. If  show that  

Ans. Given:    ……….(i)

Changing  to  in eq. (i), 

L.H.S. = 

= R.H.S. [changing  to  in eq. (i)]

 

 

Ques.14. Show that:

(i)  

(ii)  

Ans. (i) L.H.S. =  =  = 

R.H.S. =  =  = 

  L.H.S.  R.H.S.

(ii) L.H.S. = 

R.H.S. = 

  L.H.S.  R.H.S.

 

 

Ques.15. Find A2 – 5A + 6I if A = .

Ans. A2 – 5A + 6I = 

 = 

 

 

Ques.16. If A =  prove that A3 – 6A2 + 7A + 2I = 0.

Ans. L.H.S. = A3 – 6A2 + 7A + 2I

 = 

 = 

 = 0 (Zero matrix)

= R.H.S.     

hance Proved.

 

 

Ques.17. If A =  and I =  find  so that  

Ans. Given:  A =  and I = 

     

  

  

Equating corresponding entries, we have

       

And       and        

  

Ques.18. If A =  and I is the identity matrix of order 2, show that 

Ans. L.H.S. = I + A = 

and, I – A = 

R.H.S. =  = 

 =  = 

  L.H.S. = R.H.S.       

hance Proved.

 

 

Ques.19. A trust fund has ` 30,000 that must be invested in two different types of bond. The first bond pays 5% interest per year and the second bond pays 7% interest per year. Using matrix multiplication, determine how to divide ` 30,000 in two types of bonds, if the trust fund must obtain an annual interest of (a) ` 1800, (b) ` 2000.

Ans. Let the investment in first bond = ,

investment in the second bond = `

Interest paid by first bond = 5% =  per rupee and

interest paid by second bond = 5% =  per rupee.

Matrix of investment is A =  Other Pages of this Chapter:


📘 Why Exercise 3.2 are Important?

Exercise 3.2 are created by experts to give step-by-step explanations. Around 60–70% of exam questions are based on NCERT concepts. Our 12 Mathematics I Chapter 3. Matrices solutions help you understand the core concepts and practice effectively.

✍️ Quick Revising Points as Notes in Page-1

Revision is the key to exam success. Our notes for 12 Mathematics I highlight important formulas, key definitions, and exam-ready points from Chapter 3. Matrices. These quick revision notes make last-minute preparation easy.

📚 NCERT Exercise Solutions

Every NCERT chapter ends with exercises, and solving them is crucial. Our Exercise 3.2 include complete solutions for 12 Mathematics I Chapter 3. Matrices exercises. With step-by-step answers, you gain clarity and confidence to attempt similar exam questions.

📝 Additional Important Questions & Answers

To boost your preparation, we also provide additional important questions with answers. These are prepared from previous year board papers, sample papers, and important concepts of Chapter 3. Matrices. Practicing these ensures you are well-prepared for both board and mid-term exams.

🎯 Useful for Board & Mid-Term Exams

Our Exercise 3.2 are useful for both board exams and mid-term exams. For 12 Mathematics I, we provide notes, exercises, and important Q&A so that you can revise smartly and write perfect answers in exams.

🌟 Final Words

In short, Exercise 3.2 for 12 Mathematics I Chapter 3. Matrices are a complete study package. With quick revising points, NCERT exercises, and additional important questions, you can prepare effectively for exams. Make these solutions your study companion and excel in your academic journey.

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