Verify the identity: 2cos4xsin2x=2sin3xcos3x-2cosxsinx.

I know I have to use the product to sum identities but im still stuck.

So far I have, sin(3x+3x)+sin(3x-3x)-sin(x+x)-sin(x-x)

What happens to the sin after you subtract 3x-3x and x-x?

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- April 6th 2008, 03:55 PMkelsey3Stuck with trig identities
Verify the identity: 2cos4xsin2x=2sin3xcos3x-2cosxsinx.

I know I have to use the product to sum identities but im still stuck.

So far I have, sin(3x+3x)+sin(3x-3x)-sin(x+x)-sin(x-x)

What happens to the sin after you subtract 3x-3x and x-x? - April 6th 2008, 04:42 PMSoroban
Hello, kelsey3!

We need this double-angle identity: .

And this sum-to-product identity: .

Quote:

Verify the identity: .

The right side is: .

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- April 6th 2008, 04:54 PMkelsey3
Thank you sooo much!