InterviewSolution
Saved Bookmarks
| 1. |
The vectors a=2hati+hatj-2hatk, b=hati+hatj. If c is a vector such that a.c=|c| and |c-a|=2sqrt2, angle between axxb and c is 45^(@), then |(axxb)xxc| is |
|
Answer» 3 `therefore |C-a|^(2) =|c|^(2) +|a|^(2) -2C*a=8` `=|c|^(2)+9-2|c| =8 RARR |c| = 1` Now , ` a xx b = | (hati , hatj , hatk ) , ( 2, 1 , -2), (1, 1 , 0)|=2 hati - 2 hatj+ hatk ` ` rArr | a xx b| = sqrt( 2^(2) +(-2)^(2)+1^(2))=3` `therefore|(a xx b) xx c|=|a xx b||c|sin 45^(@) = 3(1) ((1)/(sqrt(2)))=(3sqrt(2))/(2)` |
|