Question

Needing help with study guide...

Answer 1

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

Answer 2

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

Answer 3

it's 4/9

Answer 4

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

Answer 5

No just cos2x no exponent

Answer 6

I just noticed by cos2x you meant cos^2x

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

Answer 7

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

Answer 8

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

Answer 9

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