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Trig question

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I don't know how to find the right answer for cos (2theta) ?
Reply 1
Do you have a formula for cos(2A) in terms of sinA?

Usually called the double angle formula.

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(edited 8 years ago)
Original post by Airess3
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I don't know how to find the right answer for cos (2theta) ?


As the above user has suggested, you need to apply the double angle formula as, for example, sin2θ2sinθ\sin2 \theta \neq 2\sin\theta.

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