There's no Trig Identity for this is there?

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Strill
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There's no Trig Identity for this is there?

Postby Strill » Mon Oct 17, 2011 10:39 pm

For a wave described by:
A*sin(x)+B*sin(x-PI/3)

I'd like to describe it in terms of a single sine or cosine function.

It does reduces to A * sqrt(3) *sin(x-PI/6), but only if A=B

I can't seem to find any identity that would work if A is not equal to B though. Am I right in assuming that it's not possible to describe this wave in terms of a single sine or cosine function when A is not equal to B?

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stapel_eliz
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Postby stapel_eliz » Tue Oct 18, 2011 1:12 am

Strill wrote:For a wave described by: A*sin(x)+B*sin(x-PI/3)

I'd like to describe it in terms of a single sine or cosine function.

Is this the sort of thing you're looking for? :wink:

Wikipedia wrote:More generally, for an arbitrary phase shift, we have



where



and


Strill
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Re: There's no Trig Identity for this is there?

Postby Strill » Tue Oct 18, 2011 6:19 pm

Yes, thank you that's exactly what I was looking for.


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