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CUET · MATHS · PYQ PAPER 2025

Cosine of the acute angle between the lines \(\frac{x-3}{2}=\frac{y-2}{1}=\frac{x-5}{2}\) and \(\frac{x-1}{6}=\frac{y-3}{-3}=\frac{z+6}{2}\) is

  1. A \(\frac{11}{21}\)
  2. B \(\frac{13}{21}\)
  3. C \(\frac{10}{21}\)
  4. D \(\frac{8}{21}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{13}{21}\)

Step-by-step Solution

Detailed explanation

Direction vectors are \(\vec{d_1} = \langle 2, 1, 2 \rangle\) and \(\vec{d_2} = \langle 6, -3, 2 \rangle\). \(\cos\theta = \frac{|\vec{d_1} \cdot \vec{d_2}|}{||\vec{d_1}|| ||\vec{d_2}||}\) \(\vec{d_1} \cdot \vec{d_2} = (2)(6) + (1)(-3) + (2)(2) = 12 - 3 + 4 = 13\)…