Double angle identies - Simplify the expression

calc1

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Feb 26, 2013
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I've lost my identities again!

I have mixed them up but don't see how to manipulate the expression.

Please help simplify:

cos2(x)/2sin(x)cos(x)
 
I've lost my identities again!

I have mixed them up but don't see how to manipulate the expression.

Please help simplify:

cos2(x)/2sin(x)cos(x)

As written - following PEMDAS - your problem is:

\(\displaystyle \dfrac{cos2(x)}{2}*sin(x)*cos(x)\ \)

What do you want to do with that expression? Please be specific and share your work.
 
What do you want to do with that expression? Please be specific and share your work.

Okay. More parentheses. I am in a section of my course on double-angle identities. The only instruction for this exercise is: Simplify
I have tried using different variations of the double-angle formulas but don't see a way to develop the problem.

(cos2(x)-sin2(x))/sin2(x) . . ?

(cos2(x)-sin2(x))/(2sin(x)cos(x)) . . ?

(2cos2(x)-1)/sin2(x) . . ?

(2cos2(x)-1)/(2sin(x)cos(x)) . . ?

(1-2sin2(x))/sin2(x) . . ?

(1-2sin2(x))/(2sin(x)cos(x)) . . ?

It is possible that this problem is accidentally from a future section, Other Advanced Identities, that covers cofunction, power-reducing, and half-angle identities.

Original problem: cos2(x)/(2sin(x)cos(x))
 
Last edited:
Hello, calc1!

You are expected to know this identity: .\(\displaystyle \sin2\theta \,=\,2\sin\theta\cos\theta\)


\(\displaystyle \text{Simplify: }\:\dfrac{\cos2x}{2\sin x\cos x}\)

\(\displaystyle \displaystyle \frac{\cos2x}{2\sin x\cos x} \;=\;\frac{\cos2x}{\sin2x} \;=\;\cot2x\)
 
Thanks soroban. I looked back a my scribblings and of all the permutations, I missed that one! I tend to look for every problem to have a lengthy solution.
 
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