Double Angle Formulae (Edexcel A Level Maths) : Revision Note
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Double Angle Formulae
What are the double angle formulae?
The double angle formulae are derived from the 'A+B' versions of the compound angle formulae:



Examiner Tips and Tricks
The double angle formulae are not included in the formulae booklet – you have to know them.
If you forget them, you can always derive them from the compound angle formulae (which are in the formula booklet) as shown above.
Worked Example

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