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Math Help - simplifying trignometry in calculus

  1. #1
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    simplifying trignometry in calculus

    How does this simplify to sin3x:

    sinxcos2x + sin2xcosx = sin3x

    this is part of parametric equations ch10 in my Calculus textbook. I am not sure if they used a trig identity or pure algebra.

    thank you
    Last edited by mr fantastic; January 11th 2010 at 03:19 AM. Reason: Removed spectacularly unsuccessful image link.
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  2. #2
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    Are you asking a question different to sinAcosB+cosAsinB=sin(A+B) ?
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  3. #3
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    Thanks for the help. You are right about that identity.

    I knew the Calculus but it is only the trig and algebra which costs me points on the Calculus exam.

    Thanks again. So How do I give you exp points for helping me out so the green balls will
    increase on your account.
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  4. #4
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    Here's a reasonable list of trig identities.
    I don't know about the green dots either!
    you're welcome.
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  5. #5
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    Quote Originally Posted by bhaskar2 View Post
    Thanks for the help. You are right about that identity.

    I knew the Calculus but it is only the trig and algebra which costs me points on the Calculus exam.

    Thanks again. So How do I give you exp points for helping me out so the green balls will
    increase on your account.
    Click on the "thanks" button below the post.
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