NCERT Example 7 - Three Dimensional Geometry
Question: Find the angle between the lines r⃗ = 3î + 2ĵ − 4k̂ + λ(î + 2ĵ + 2k̂) and r⃗ = 5î − 2ĵ + μ(3î + 2ĵ + 6k̂).
Answer: θ = cos⁻¹(19/21).
Full step-by-step NCERT solution with diagrams on Something by Zero.