BITSAT2019MathematicsVector AlgebraActual
If a → = i ^ + 2 j ^ + 3 k ^ , b → = - i ^ + 2 j ^ + k ^ , c → = 3 i ^ + j ^ and a → + p b → is normal to c → , then p is equal to
Options
- A0
- B1
- C5
- D3
Correct answer
C. 5
Step-by-step solution
a → + p b → is normal to c → ∴   a → + p b → · c → = 0 1 - p i ^ + 2 + 2 p j ^ + 3 + p k ^ · 3 i ^ + j ^ = 0 3 - 3 p + 2 + 2 p = 0 ⇒ p = 5