SOLUTION: sin^3 3x=(1/2)(sin 3x)(1-cos 6x) I need help proving this identity, it is my final problem on my worksheet and I am completely stumped. thank you tons!!!!! Nicolas

Algebra ->  Trigonometry-basics -> SOLUTION: sin^3 3x=(1/2)(sin 3x)(1-cos 6x) I need help proving this identity, it is my final problem on my worksheet and I am completely stumped. thank you tons!!!!! Nicolas      Log On


   

Question 575481: sin^3 3x=(1/2)(sin 3x)(1-cos 6x)
I need help proving this identity, it is my final problem on my worksheet and I am completely stumped.
thank you tons!!!!!
Nicolas
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Now that I have managed to unstump myself...

First consider the case in which case the equation reduces to .

Next consider , so allowing:



which yields:



Still ugly, but an improvement.

Let , then



And



Then use

to write:



Then use

to write:



and finally



Hence




John

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