How do I factor this?
cos22X + cos2X = 0
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Hi Aceradonia ! Welcome to PF!
Well, cos22X is the same as (cos2X)2,
so you can factor out a cos2X.
hmm … did you mean solve, rather than factor? … then cos2x = 0 is one set of solutions, and the other is … ?
You will easy realise it, maybe (not necessarily) if you substitute for cos2X=y, you will come up with y2+y=0. Out of there: y(y+1)=0
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