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Math Help - Simple Differentiation help

  1. #1
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    Simple Differentiation help

    i need to differentiate these 3 functions.
    for a, am i supposed to use the quotient rule ? or would it just be 3x^2/1?
    x by itself is equal to 1 right?
    and constants are mostly ignored except for special situations?


    Any help is appreciated, as i'm just learning how to do this and i don't have a textbook..



    a) x^3+2 / x-5


    3x^2(x-5) 1 (x^3+2)/(x-5)^2

    b) (2x^4 + x)(-4x^2 + 1)
    c) Find dy/dx if y=2u^3 5u , u=x^3+2
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  2. #2
    Member mfetch22's Avatar
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    Columbus, Ohio, USA
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    Quote Originally Posted by seanP View Post
    i need to differentiate these 3 functions.
    for a, am i supposed to use the quotient rule ? or would it just be 3x^2/1?
    x by itself is equal to 1 right?
    and constants are mostly ignored except for special situations?


    Any help is appreciated, as i'm just learning how to do this and i don't have a textbook..



    a) x^3+2 / x-5


    3x^2(x-5) 1 (x^3+2)/(x-5)^2

    b) (2x^4 + x)(-4x^2 + 1)
    c) Find dy/dx if y=2u^3 5u , u=x^3+2
    Yes, for the first one we have:

    y=\frac{x^3+2}{x-5}

    And use the quotient rule to get:

    \frac{dy}{dx} = \frac{(3x)(x-5)-(x^3+2)}{(x-5)^2}

    For the third one we have (by substituting the u in):

    y=2(x^3+2)^3-5(x^3+2)

    By using the chain rule on the exponents we get the following:

    \frac{dy}{dx} = (6)(x^3+2)^2(3x^2)-15x^2

    I figured you could figure out the second problem by these examples, but if you still want some help post here and I'll help some more
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  3. #3
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    thanks for clearing that up
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