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CUET · MATHS · PYQ PAPER 2023

If \(\vec{a}, \vec{b}, \vec{c}\) are unit vectors such that \(\vec{a}+\vec{b}+\vec{c}=\overrightarrow{0}\), then the value of \(\vec{a} \cdot \vec{b}+\vec{b} \cdot \vec{c}+\vec{c} \cdot \vec{a}\) is:

  1. A \(\frac{1}{2}\)
  2. B \(\frac{3}{2}\)
  3. C \(-\frac{3}{2}\)
  4. D 0
Verified Solution

Answer & Solution

Correct Answer

(C) \(-\frac{3}{2}\)

Step-by-step Solution

Detailed explanation

\((\vec{a}+\vec{b}+\vec{c})^2 = (\overrightarrow{0})^2\) \(\|\vec{a}\|^2 + \|\vec{b}\|^2 + \|\vec{c}\|^2 + 2(\vec{a} \cdot \vec{b} + \vec{b} \cdot \vec{c} + \vec{c} \cdot \vec{a}) = 0\)…
From CUET
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