Classical Dynamics of Particles and Systems · Problem 1-17

Newtonian Mechanics—Single Particle — Marion & Thornton

Physics — Mechanics · vector-algebra-trigonometry

Problem

Obtain the cosine law of plane trigonometry by interpreting the product

(\mathbf{A} - \mathbf{B}) \cdot (\mathbf{A} - \mathbf{B})

and the expansion of the product.