NTA Abhyas JEE Main2020MathematicsVector AlgebraPractice
If a → , b → , c → are non coplanar non - zero vectors such that b → × c → = a → , a → × b → = c → and c → × a → = b → , then which of the following is not true
Options
- Aa → = 1
- Ba → b → c → = 1
- Ca → + b → + c → = 3
- Da → ≠ b → ≠ c →
Correct answer
D. a → ≠ b → ≠ c →
Step-by-step solution
b → × c → = a → ⇒ a → b → c → = a → . a → = a → 2 Similarly, a → b → c → = b → 2 = c → 2 ∴ a → = b → = c → = a → b → c → Now, b → × c → c → × a → a → × b → = a → b → c → 2 ∴ a → b → c → = a → b → c → 2 But, a → b → c → ≠ 0 (non-coplanar) So a → b → c → = 1 Hence a → = b → = c → = 1