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Math Help - Differentiation with trigonometry

  1. #1
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    Differentiation with trigonometry

    Can someone please show me how this happens?

    y = (1+sin^2 x)^3

    y'= 3sin2x (1+sin^2 x)^2


    because I thought that the differentiated form of sin^2x = 2sinxcosx
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  2. #2
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    Quote Originally Posted by CSG18 View Post
    Can someone please show me how this happens?

    y = (1+sin^2 x)^3

    y'= 3sin2x (1+sin^2 x)^2


    because I thought that the differentiated form of sin^2x = 2sinxcosx
    Note that 2\sin(x) \cos(x) = \sin(2x).

    y' = 6\sin(x) \cos(x) (1+ \sin^2 x)^2 is equally correct.
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  3. #3
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    Quote Originally Posted by e^(i*pi) View Post
    Note that 2\sin(x) \cos(x) = \sin(2x).

    y' = 6\sin(x) \cos(x) (1+ \sin^2 x)^2 is equally correct.
    Oh yes of course! Thank you very much, I can't believe I didn't spot that.
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