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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- Dec 14th 2007, 11:49 AMcompuwizProving a Trig Identity
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 - Dec 14th 2007, 11:58 AMgalactus
You can use the identity:

$\displaystyle tan^{2}(x)=\frac{1-cos(2x)}{1+cos(2x)}$

It'll fall into place. - Dec 14th 2007, 12:03 PMcompuwiz
thanks so much

- Dec 14th 2007, 12:44 PMKrizalid