1. Class 12
  2. Sample Papers, Previous Year Papers and Other Questions
  3. CBSE Class 12 Sample Paper for 2019 Boards

Question 6 - CBSE Class 12 Sample Paper for 2019 Boards

Last updated at Nov. 1, 2018 by

Question 6

If A = [3 1 -1 2] and I = [1 0 0 1], find k so that A 2 = 5A + kI

Slide13.JPG

Slide14.JPG
Slide15.JPG

  1. Class 12
  2. Sample Papers, Previous Year Papers and Other Questions

    3. CBSE Class 12 Sample Paper for 2019 Boards

    CBSE Class 12 Sample Paper for 2018 Boards →
Ask Download

Transcript

Question 6 If A = [■8(3&1@−1&2)] and I = [■8(1&0@0&1)], find k so that A2 = 5A + kI Finding A2 A2 = [■8(3&1@−1&2)] [■8(3&1@−1&2)] A2 = [■8(3(3)+1(−1)&3(1)+1(2)@−1(3)+2(−1)&−1(1)+2(2))] A2 = [■8(9−1&3+2@−3−2&−1+4)] A2 = [■8(8&5@−5&3)] Finding 5A 5A = 5[■8(3&1@−1&2)] 5A = [■8(5×3&5×1@5×(−1)&5×2)] 5A = [■8(15&5@−5&10)] Now, our equation is A2 = 5A + kI Putting values [■8(8&5@−5&3)] = [■8(15&5@−5&10)] + k [■8(1&0@0&1)] [■8(8&5@−5&3)] = [■8(15&5@−5&10)] + [■8(𝑘×1&𝑘×0@𝑘×0&𝑘×1)] [■8(8&5@−5&3)] = [■8(15&5@−5&10)] + [■8(𝑘&0@0&𝑘)] [■8(8&5@−5&3)] = [■8(15+𝑘&5+0@−5+0&10+𝑘)] [■8(8&5@−5&3)] = [■8(15+𝑘&5@−5&10+𝑘)] Thus, 8 = 15 + k 8 – 15 = k –7 = k k = –7

Class 12
Sample Papers, Previous Year Papers and Other Questions

About the Author

Davneet Singh's photo - Teacher, Computer Engineer, Marketer
Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.