How do you decide which of the 3 cosine double-angle identities you need to use? I think I get how to use each formula, but I just can't figure out when to use which one.

Guest Mar 14, 2017

1+0 Answers


I'm sure there are people here who can help. :)

Can you give an example of one of your problems?

hectictar  Mar 14, 2017

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