My Year 13 class have just finished C3 and actually asked a very sensible set of questions:

• Which formulae are given to you?
• Which formulae must you learn?
• Which formulae can you work out from given rules?
• How do you prove simple rules?

In response to this, I’ve written a booklet for the Edexcel C3 paper: Trigonometry and Differentiation: What you are given and what you need to learn (docx) ( PDF Version)