Question

If the magnitude of two vectors are 3 and 4 and their scalar product is 6, find angle between them and also find \(|\vec A \times \vec B|\)

Answer 1

\(\vec A.\vec B\) = AB cos θ

\(|\vec A \times \vec B|\) = AB sin θ

or 6 = (3 x 4) cos θ = 3 x 4 x 60°

or θ = 60°

3 x 4 x \(\frac{\sqrt3}{2}\) = 6\(\sqrt3\)