• Able to understand and derive the formulae for Compound Angle (Sum & Difference), Double Angle, Factor and R-Formulae
  • Able to use the above formulae to simplify trigo expressions, solve trigo equations, prove trigo identities etc.

Resources: Marshall Cavendish TB Ch 11-13
Download slides for entire topic:

(1) Compound Angle (a.k.a Sum & Difference/Addition Formulae)

The textbook gives a proof of the formulae. Here is an ONE alternative proof:

And ANOTHER proof using Ptoleny's Theorem here:

(2) Double Angle Formulae

Video 1: Derivation of Double Angle Formulae

Direct Link: http://www.youtube.com/watch?v=rn0JuZGMu0s

Video 2: Applications of Double Angle Formulae

Direct Link: http://www.youtube.com/watch?v=8NlV4z-2lMo

Slides used in class:

(3) R-Formulae


Applet to demonstrate Max and Min Points:

(4) Factor Formulae


Solutions to examples and exercises:

Quizes & Solutions:

Challenging Practices: