Thread: Sum and Difference formulae (sin and cos)

I'm just curious about the,



identities, is there a simple way to derive them?

I have a test in a few days and I don't like memorizing too much.

Thanks again!

No simple way to derive them I'm afraid - more time and effort than you can afford to waste in a test.

Just write them down and/or memorise them.



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If I can memorise them you can too :P