ExamBro
ExamBro
AP EAMCET · Maths · Vector Algebra

If \(\bar{a}, \bar{b}, \bar{c}\) are three unit vectors such that \(|\bar{a}-\bar{b}|^2+|\bar{b}-\bar{c}|^2+|\bar{c}-\bar{a}|^2=15\), then \(|\bar{a}-\bar{b}-\bar{c}|^2-4(\bar{b} \cdot \bar{c})=\)

  1. A \(6\)
  2. B \(15\)
  3. C \(12\)
  4. D \(10\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(12\)

Step-by-step Solution

Detailed explanation

\( |\bar{a}-\bar{b}|^2+|\bar{b}-\bar{c}|^2+|\bar{c}-\bar{a}|^2=15 \) \( (|\bar{a}|^2+|\bar{b}|^2-2\bar{a}\cdot\bar{b})+(|\bar{b}|^2+|\bar{c}|^2-2\bar{b}\cdot\bar{c})+(|\bar{c}|^2+|\bar{a}|^2-2\bar{c}\cdot\bar{a})=15 \)…