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Math Help - derivative of trig function using product rule

  1. #1
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    derivative of trig function using product rule

    I have to differentiate 8x^2 sinx tanx

    I'm not sure if I have to use the product rule twice or If i just use 8x^2 as a constant times sinx
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  2. #2
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    Re: derivative of trig function using product rule

    Quote Originally Posted by neontiger94 View Post
    I have to differentiate 8x^2 sinx tanx
    If y=f\cdot g\cdot h then y^{\prime}=(f^{\prime}\cdot g+f\cdot g^{\prime})\cdot h+(f\cdot g)\cdot h^{\prime}
    Thanks from neontiger94
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  3. #3
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    Re: derivative of trig function using product rule

    Quote Originally Posted by Plato View Post
    If y=f\cdot g\cdot h then y^{\prime}=(f^{\prime}\cdot g+f\cdot g^{\prime})\cdot h+(f\cdot g)\cdot h^{\prime}
    Which becomes the easy-to-remember f' \cdot g \cdot h + f \cdot g' \cdot h + f \cdot g \cdot h'.

    - Hollywood
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    Re: derivative of trig function using product rule

    Quote Originally Posted by hollywood View Post
    Which becomes the easy-to-remember f' \cdot g \cdot h + f \cdot g' \cdot h + f \cdot g \cdot h'.
    I agree that it is easy-to-remember, but is it easy to understand how it comes about?
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  5. #5
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    Re: derivative of trig function using product rule

    You're right - it's definitely easier to see how (f' \cdot g+f \cdot g') \cdot h+(f \cdot g) \cdot h comes about.
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