# Thornton & Marion, Classical Dynamics (5th Edition)

# Chapter 1. Matrices, Vectors, and Vector Calculus

# Problem 19. Vector Algebra

## The problem asks you to derive

- Angle transformation formulae using vector algebra.

## You should know about

- The basic concept of a vector algebra
- Law of cosines
- Pythagorean trigonometric identity

## Solution

## References

https://en.wikipedia.org/wiki/Law_of_cosines

https://en.wikipedia.org/wiki/Pythagorean_trigonometric_identity