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Mathematics 7 Online
OpenStudy (anonymous):

Needing help with study guide...

OpenStudy (anonymous):

Find the exact value for cos2x given sinx = √2/3 1 5/9 4/9 0

OpenStudy (anonymous):

cos(2x) = cos^2x - sin^2x = (1 - sin^2x) - sin^2x = 1 - 2sin^2x

OpenStudy (anonymous):

it's 4/9

OpenStudy (anonymous):

Can you explain how to do it my teacher makes no sense :/

OpenStudy (anonymous):

No just cos2x no exponent

OpenStudy (anonymous):

I just noticed by cos2x you meant cos^2x cos^2x = 1 - sin^2x = 1 - (sinx)^2

OpenStudy (anonymous):

well if you actually meant cos(2x), then the right answer is not on the list

OpenStudy (anonymous):

hmm... It just says cos2x it doesnt look like its an exponent at all..

OpenStudy (anonymous):

@6forever can you explain how you got 4/9?

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