Prove that this equation is true.

sin22a-sin2a=sin3a x sina

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- May 4th 2008, 10:30 AMblerttatrigonometric identity
Prove that this equation is true.

sin22a-sin2a=sin3a x sina - May 4th 2008, 10:48 AMReckoner
I really don't understand your question. Do you mean

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?

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Please be more careful with your notation. - May 4th 2008, 02:27 PMblertta
- May 4th 2008, 02:42 PMReckoner
- May 5th 2008, 04:23 AMblertta
- May 5th 2008, 04:42 AMtopsquark
Then you want to solve the equation for a.

My calculator comes up with 18 solutions. I would not be surprised if there were actually 22 possibles (thus leaving 4 complex solutions.) Generally an equation with in it will reduce to an nth degree polynomial so you would be stuck solving a 22nd degree polynomial equation, which is impossible to do in general. You are going to be stuck doing numerical approximations.

However notice that there is at least one nice solution: a = 0.

-Dan