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February 23rd, 2017, 05:04 AM   #1
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questions involving double angles

Hello everyone... again

I've been given a couple of questions and I have no flipping idea how to do them. The teacher has been over double angle identities with us but the following questions have left me stumped, even with all my notes and textbook out.

so here it is:

Solve the equation

$\sqrt{3}\cos2x-\sin x \cos x-1=0

The main problem here is that I'm not quite sure how to simplify it.

Thanks for reading! Looking forward to some enlightenment.

Last edited by skipjack; February 23rd, 2017 at 05:52 AM.
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February 23rd, 2017, 05:58 AM   #2
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Is it possibly $\dfrac{\sqrt{3}}{2}\cos(2x) - \sin(x)\cos(x)-1=0$?

Last edited by skipjack; February 23rd, 2017 at 06:11 AM.
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February 23rd, 2017, 02:23 PM   #3
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Start with sinxcosx=(sin2x)/2. Try solving for 2x.
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