In this video tutorial, I show you how to express multiple angles for sin(nθ) or cos(nθ) in terms of sinθ and cosθ using De Moivre’s theorem.
Express the following:
cos(4θ) in terms of cosθ

Example

Here is an example for you to try which follows up the tutorial on how to express multiple angles for sin(nθ) or cos(nθ) in terms of sinθ and cosθ using De Moivre’s theorem.
Express the following:

  1. cos(5θ) in terms of cosθ
  2. sin(5θ) in terms of sinθ