Question

The angle between the lines whose direction cosines are given by the equations \( 3l + m + 5n = 0 \) and \( 6m - 2n + 5l = 0 \) is:

• A. \( \cos^{-1} \left( \frac{1}{6} \right) \)
• B. \( \cos^{-1} \left( -\frac{1}{6} \right) \)
• C. \( \cos^{-1} \left( \frac{2}{3} \right) \)
• D. \( \cos^{-1} \left( -\frac{5}{6} \right) \)

Hint:

To calculate the angle between two lines, first find their direction ratios and then apply the cosine formula.