NDA2013MathematicsVector AlgebraActual
The position vectors of the points A and B are respectively 3 i -5 j +2 k and i + j - k . What is the length of A B ?
Options
- A11
- B9
- C7
- D6
Correct answer
C. 7
Step-by-step solution
aligned AB & =(3-1) i +(-5-1) j +(2-(-1)) k & =2 i -6 j +3 k | AB | & = (2)^2+(-6)^2+(3)^2 & = 4+36+9 = 49 =7 units. aligned