Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • Let <img alt="\mathrm{A=\left[\begin{array}{l} 1 \\ 1 \\ 1 \end{array}\right] \text { and } B=\left[\begin{array}{ccc} 9^{2} & -10^{2} & 11^{2} \\ 12^{2} & 13^{2} & -14^{2} \\

Let \mathrm{A=\left[\begin{array}{l} 1 \\ 1 \\ 1 \end{array}\right] \text { and } B=\left[\begin{array}{ccc} 9^{2} & -10^{2} & 11^{2} \\ 12^{2} & 13^{2} & -14^{2} \\ -15^{2} & 16^{2} & 17^{2} \end{array}\right]}, then the value of \mathrm{A^{\prime} B A} is:

Option: 1

1224


Option: 2

1042


Option: 3

540


Option: 4

539


Answers (1)

best_answer

\mathrm{A^{\prime} B} =\left[\begin{array}{lll} 1 & 1 & 1 \end{array}\right]\left[\begin{array}{ccc} 9^{2} & -10^{2} & 11^{2} \\ 12^{2} & 13^{2} & -14^{2} \\ -15^{2} & 16^{2} & 17^{2} \end{array}\right] \\ 

         =\left[\begin{array}{lll} 9^{2}+12^{2}-15^{2} & -10^{2}+13^{2}+16^{2} & 11^{2}-14^{2}+17^{2} \end{array}\right]

\text { (A'B) } A =\left[9^{2}+12^{2}-15^{2}-10^{2}+13^{2}+16^{2} 11^{2}-14^{2}+17^{2}\right]\left[\begin{array}{l} 1 \\ 1 \\ 1 \end{array}\right] \\

                 =\left[9^{2}+12^{2}-15^{2}-10^{2}+13^{2}+16^{2}+11^{2}-14^{2}+17^{2}\right] \\

                 =\left[\left(9^{2}-10^{2}\right)+\left(11^{2}+12^{2}\right)+\left(13^{2}-14^{2}\right)\right.\\                             \left.+\left(-15^{2}+16^{2}\right)+17^{2}\right] \\

                =[-19+265-27+31+289] \\

                =[539]

Hence correct option is 4

 

Posted by

Ajit Kumar Dubey

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

Bihar Board extends BSEB Super 50 free coaching application last date to March 26
anam-khan

JEE Main 2025: Most important chapters for physics, chemistry, mathematics to score good marks
anam-khan

JEE Main 2025 session 2 dates clash with ISC, PSEB 12th exams; no impact on major science subjects

Latest Question