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## aussy123 2 years ago x = -135, cos 2x = 1 - 2 sin2x True False I think its true, but when I was using the unit circle, I couldnt find -135

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1. aussy123

@Chlorophyll can you help me, please?

2. Hoa

hi friend, your problem is $\cos 2x = 1 - 2 \sin^2 x ?$

3. Hoa

if mine is right, so, the answer is true. if yours is right, the answer is false. why? because we have a formula for that trig: it's mine. it's true with any value of x. Hope this helps

4. aussy123

Thanks you, I was having a big problem with this, and I moved to the next questions. Thank YOU SO MUCH!

5. Hoa

thanks for your medal.

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