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How To Find The Sin(A+B)=SinA.CosB+CosA.SinB?

  1. Jul 12, 2012 #1
    Hi everyone,

    I wonder why Sin(A+B)=SinA.CosB+CosA.SinB?

    Huygen
     
  2. jcsd
  3. Jul 12, 2012 #2

    phyzguy

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    Science Advisor

    The easiest way to see this is to use Euler's formula:
    [tex]e^{ix} = cos(x) + i sin(x)[/tex]

    put in A+B for x, expand it, and collect real and imaginary parts.
     
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