ExamBro
ExamBro
MHT CET · Maths · Vector Algebra

Let \(\bar{a}\) and \(\bar{c}\) be unit vectors at an angle \(\frac{\pi}{3}\) with each other. If \((\bar{a} \times(\bar{b} \times \bar{c})) \cdot(\bar{a} \times \bar{c})=5\), then \(\left[\begin{array}{lll}\bar{a} & \bar{b} & \bar{c}\end{array}\right]=\)

  1. A \(10\)
  2. B \(-10\)
  3. C \(9\)
  4. D \(-9\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(-10\)

Step-by-step Solution

Detailed explanation

\((\bar{a} \times(\bar{b} \times \bar{c})) \cdot(\bar{a} \times \bar{c}) = ((\bar{a} \cdot \bar{c})\bar{b} - (\bar{a} \cdot \bar{b})\bar{c}) \cdot (\bar{a} \times \bar{c}) = 5\) \((\bar{a} \cdot \bar{c}) (\bar{b} \cdot (\bar{a} \times \bar{c})) - (\bar{a} \cdot \bar{b}) (\bar{c} \cdot (\bar{a} \times \bar{c})) = 5\)