Hi there, I need help proving a trig ident. steps plz, cos2x= (1-tan^2(x)) ..........(1+tan^2(x)) tan^2(x) is tan(x)^2....if u don't understand my writing Please, any help is appreciated, thanks
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You can use the identity: It'll fall into place.
thanks so much
Originally Posted by compuwiz cos2x= (1-tan^2(x)) ..........(1+tan^2(x)) (Basic identity.) Now split the original fraction into two sums: And this is exactly equal to double-angle cosine formula.
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