Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Three-dimensional Geometry

Question:

The angle between the pair of lines \(\frac{x+3}{3}=\frac{y-1}{5}=\frac{z+3}{4}\) and \(\frac{x+1}{1}=\frac{y-4}{1}=\frac{z-5}{2}\) is

Options:

\(\cos^{-1}\left(\frac{4\sqrt{3}}{15}\right)\)

\(\cos^{-1}\left(\frac{8\sqrt{3}}{15}\right)\)

\(\cos^{-1}\left(\frac{2\sqrt{3}}{15}\right)\)

\(\sin^{-1}\left(\frac{8\sqrt{3}}{15}\right)\)

Correct Answer:

\(\cos^{-1}\left(\frac{8\sqrt{3}}{15}\right)\)

Explanation:

\(\cos \theta=\left|\frac{a_{1}a_{2}+b_{1}b_{2}+c_{1}c_{2}}{\sqrt{a_{1}^2+b_{1}^2+c_{1}^2}\sqrt{a_{2}^2+b_{2}^2+c_{2}^2}}\right|\)