If (2i + 6j + 27k ) × (i + pj + qk ) = 0 , then the values of p and q are?

(a) p = 6, q = 27                  (b) p = 3, q = 27/2  

(c) p = 6, q = 27/2               (d) p = 3,  q = 27

Slide4.JPG

Slide5.JPG

  1. Class 12
  2. Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Transcript

Question 3 If (2๐‘– ฬ‚ + 6๐‘— ฬ‚ + 27๐‘˜ ฬ‚ ) ร— (๐‘– ฬ‚ + p๐‘— ฬ‚ + q๐‘˜ ฬ‚) = 0 โƒ— , then the values of p and q are? (a) p = 6, q = 27 (b) p = 3, q = 27/2 (c) p = 6, q = 27/2 (d) p = 3, q = 27 Given (2๐‘– ฬ‚ + 6๐‘— ฬ‚ + 27๐‘˜ ฬ‚ ) ร— (๐‘– ฬ‚ + p๐‘— ฬ‚ + q๐‘˜ ฬ‚) = 0 โƒ— Therefore, |โ– 8(๐‘– ฬ‚&๐‘— ฬ‚&๐‘˜ ฬ‚@2&6&27@1&๐‘&๐‘ž)|=0๐‘– ฬ‚+0๐‘— ฬ‚+0๐‘˜ ฬ‚ ๐‘– ฬ‚(6q โ€“ 27p) โ€“ ๐‘— ฬ‚(2q โ€“ 27) + ๐‘˜ ฬ‚(2p โ€“ 6) = 0๐‘– ฬ‚+0๐‘— ฬ‚+0๐‘˜ ฬ‚ Comparing 6q โ€“ 27p = 0 2q โ€“ 27 = 0 2q = 27 q = 27/2 2p โ€“ 6 = 0 2p = 6 p = 6/2 = 3 Therefore, p = 3, q = ๐Ÿ๐Ÿ•/๐Ÿ So, (b) is the correct answer

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 9 years. He provides courses for Maths and Science at Teachoo.