Hi I've got this problem which has really been bothering me.(adsbygoogle = window.adsbygoogle || []).push({});

How are you supposed to prove that:

(Sin[A] Sin[2 A] + Sin[3 A] Sin[6 A])/(Sin[A] Cos[2 A] + Sin[3 A] Cos[6 A]) is identicle to tan[5A].

I am almost sure that I've got to use the factor formulae, but I've had no luck. Maybe someone can help me please :)

Thank you for your time!

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# Homework Help: Help with proving a trigonometric identity

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