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  • Perplex
    IB Math AISL
    /
    Differentiation
    /

    Limits and Derivatives

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    Exercises

    Key Skills

    Limits and Derivatives

    Limits and Derivatives

    The concept (and basic properties) of limits and derivatives

    Want a deeper conceptual understanding? Try our interactive lesson!

    Exercises

    No exercises available for this concept.

    Practice exam-style limits and derivatives problems

    Key Skills

    Basic concept of a limit
    SL 5.1

    The limit ​x→alim​f(x)​ is the value ​f(x)​ approaches as ​x​ approaches ​a.

    Slope as a Limit
    SL 5.1

    The IB may test your understanding of the gradient of the curve as the limit of

    ​
    m=x2​−x1​y2​−y1​​
    ​

    as ​(x2​−x1​)​ goes to zero.


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    Limit from a graph
    SL 5.1

    Powered by Desmos

    ​
    x→1lim​f(x)=2
    ​
    ​
    x→∞lim​f(x)=23​
    ​
    ​
    x→−∞lim​f(x)=23​
    ​
    Limit from a table
    SL 5.1

    Given a table of values:

    ​
    xf(x)​0.91.62​0.991.9121​0.9991.9972201​……​
    ​


    ​
    x→1lim​f(x)=2
    ​
    Gradient
    SL 5.1

    For a curve ​y=f(x), ​f′(x)​ is the gradient or slope.

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    Graphing a derivative with a GDC
    SL 5.1

    You can graph ​f′(x)​ using the following steps:

    • Press the Y= key.

    • In one of the available function lines (e.g. Y_1), enter the expression for ​f(x).

    • In another available line (e.g. Y_2), input the derivative function usingMATH then 8:nDeriv( in the following format:

      ​
      dXd​(Y1​(x))∣X=X​
      ​


    • To enter ​Y1​, press VARS then scroll to Y-VARS and select FUNCTION then ​Y1​.

    • Press GRAPH to display both the original graph ​f​ and the derivative ​f′.

    • The graph of ​f′​ may take a little bit longer depending on the original function.

    After graphing ​f′, you may use all the other graphing functions on the calculator (intersect, zero, and value).

    Rate of Change
    SL 5.1

    ​dxdy​​ is the rate of change of ​y​ with respect to ​x​. That is, ​dxdy​​ tells us how much ​y​ changes in response to a change in ​x.


    If ​y=f(x), then ​dxdy​=f′(x).

    Derivative of xⁿ where n is an integer
    SL 5.3
    ​
    f(x)=xn, n∈Z⇒f′(x)=nxn−1📖
    ​
    Derivatives of sums and scalar multiples
    SL 5.3
    ​
    dxd​(af(x))=af′(x)🚫
    ​
    ​
    dxd​(f(x)+g(x))=f′(x)+g′(x)🚫
    ​
    ​
    dxd​(af(x)+bg(x))=af′(x)+bg′(x)🚫
    ​