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CUET · MATHS · PYQ PAPER 2023

The angle between \(x\) axis and the vector \(\hat{i}+\hat{j}+\hat{k}\) is :

  1. A \(\frac{\pi}{6}\)
  2. B \(\frac{\pi}{4}\)
  3. C \(\cos ^{-1}\left(\frac{1}{3}\right)\)
  4. D \(\cos ^{-1}\left(\frac{1}{\sqrt{3}}\right)\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\cos ^{-1}\left(\frac{1}{\sqrt{3}}\right)\)

Step-by-step Solution

Detailed explanation

\(\vec{A} = \hat{i}\) \(\vec{B} = \hat{i} + \hat{j} + \hat{k}\) \(\cos \theta = \frac{\vec{A} \cdot \vec{B}}{|\vec{A}| |\vec{B}|}\) \(\cos \theta = \frac{(\hat{i}) \cdot (\hat{i} + \hat{j} + \hat{k})}{| \hat{i} | | \hat{i} + \hat{j} + \hat{k} |}\)…