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Math Help - Trigonometric integral

  1. #1
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    Trigonometric integral

    \int sin(x)cos(nx)dx where n is a positive entire
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  2. #2
    Super Member General's Avatar
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    \displaystyle sin(A)cos(B)=\frac{sin(A-B) + sin(A+B)}{2}
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  3. #3
    MHF Contributor FernandoRevilla's Avatar
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    Use 2\sin mx\cos nx=\sin (m+n)x+\sin (m-n)x .


    Edited: Sorry, I didn't see General's post.
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  4. #4
    A Plied Mathematician
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    You could also integrate by parts twice and solve for the original integral.
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