InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Let `vec a ` be vector parallel to line of intersection of planes `P_1 and P_2` through origin. If `P_1`is parallel to the vectors `2 bar j + 3 bar k and 4 bar j - 3 bar k` and `P_2` is parallel to `bar j - bar k` and ` 3 bar I + 3 bar j `, then the angle between `vec a` and `2 bar i +bar j - 2 bar k` is :A. `pi//2`B. `pi//4`C. `pi//6`D. `3pi//4` |
|
Answer» Correct Answer - b,d Normal to plane `P_(1)` is `vecn_(1)= (2hatj+3hatk)xx)(4hatj-3hatk)=-18hati` Normal to plane `P_(2)` is Therefore, `vecn_(2)= (hatj-hatk)xx (3hati +3hatj)=3hati -3hatj-3hatk` `vecA` is parallel to `+-(vecn_(1)xx vecn_(2))=+- (-54hatj+54hatk)` Now , the angle between `vecA nad 2hati +hatj - 2hatk` is given by `cos thet=+-((-54hatj+54hatk).(2hati+hatj-2hatk))/(54sqrt2 .3)` `=+-1/sqrt2` `theta= pi//4 or 3pi//4` |
|