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Math Help - Tangent Line

  1. #1
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    Tangent Line

    Hello MHF, please help me solve this exercise.


    y=\sqrt[3]{x}

    a) find the equation of the tangent line at the point P (-1, -1).

    b) draw the graph of the curve and the tangent line at the point P.

    My doubt is, how can i find the tangent line of that function if he don't pass in point P?
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  2. #2
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    Re: Tangent Line

    Quote Originally Posted by Chipset3600 View Post
    Hello MHF, please help me solve this exercise.


    y=\sqrt[3]{x}

    a) find the equation of the tangent line at the point P (-1, -1).

    b) draw the graph of the curve and the tangent line at the point P.

    My doubt is, how can i find the tangent line of that function if he don't pass in point P?
    I'm sorry, I do not understand what do mean by the statement "if he don't pass in point P?"


    To find the line tangent to the curve f(x) = \sqrt[3]{x} at P(-1,-1) ...

    1. find f'(x), then evaluate f'(-1) , the slope of the tangent line at point P.

    2. Use the point-slope form of a linear equation ...

    y - (-1) = f'(-1)[x - (-1)]
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  3. #3
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    Re: Tangent Line

    Tangent Line-graf.pngi found the equation: y= (x/3)-(2/3) but the graph was:
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  4. #4
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    Re: Tangent Line

    have a look at this graph ...
    Attached Thumbnails Attached Thumbnails Tangent Line-tangentline.png  
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  5. #5
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    Re: Tangent Line

    wow! but why my function appears only in 1st quadrant?
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  6. #6
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    Re: Tangent Line

    Quote Originally Posted by Chipset3600 View Post
    wow! but why my function appears only in 1st quadrant?
    how are you inputting the cube root function?
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  7. #7
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    Re: Tangent Line

    Just Like you x^(1/3)
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  8. #8
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    Re: Tangent Line

    can't say why ... software issue?

    here is the free grapher I use ...

    Download | Graph
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  9. #9
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    Re: Tangent Line

    Quote Originally Posted by skeeter View Post
    can't say why ... software issue?

    here is the free grapher I use ...

    Download | Graph
    I used the Winplot.
    Thanks very much, I thought I was not knowing, but the graph betrayed me.
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