If a and b are vectors such that |a| = 2,; |b| = 7 and a; ; b = 3 i + 2 j + 6 k, then what is the acute angle between a
The logic is straightforward: solving fully: apply relevant formula, put numbers, compute. Result comes as 30°. Easy verification shows it satisfies condition.
Ref: NCERT Mathematics Class XII — Vectors and 3D Geometry
