AP Calculus AB · Topic 4.6

L'Hôpital's Rule Practice

Part of Contextual Applications of Differentiation.(CHA-3.F)

Practice questions

14

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Sample questions

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  1. Sample 1difficulty 2/5

    Evaluate limx0sin(2x)tan(3x)\displaystyle\lim_{x\to 0}\dfrac{\sin(2x)}{\tan(3x)}.

    • A

      00

    • B

      23\tfrac{2}{3}

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    • C

      32\tfrac{3}{2}

    • D

      11

    Why

    L'Hôpital: 2cos(2x)/(3sec2(3x))2/32\cos(2x)/(3\sec^2(3x)) \to 2/3.

  2. Sample 2difficulty 2/5

    Evaluate limx0ex1xx2\displaystyle\lim_{x\to 0}\dfrac{e^x - 1 - x}{x^2}.

    • A

      11

    • B

      12\tfrac{1}{2}

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    • C

      00

    • D

      22

    Why

    L'Hôpital twice: (ex1)/(2x)ex/21/2(e^x - 1)/(2x) \to e^x/2 \to 1/2.

  3. Sample 3difficulty 2/5

    Evaluate limx1x31x21\displaystyle\lim_{x\to 1}\dfrac{x^3 - 1}{x^2 - 1}.

    • A

      11

    • B

      33

    • C

      32\tfrac{3}{2}

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    • D

      22

    Why

    L'Hôpital: 3x2/(2x)=3x/23/23x^2/(2x) = 3x/2 \to 3/2 at x=1x = 1.

  4. Sample 4difficulty 2/5

    Evaluate limx01cosxx2\displaystyle\lim_{x\to 0}\dfrac{1 - \cos x}{x^2}.

    • A

      00

    • B

      11

    • C

      1-1

    • D

      12\tfrac{1}{2}

      check_circle

    Why

    0/00/0. L'Hôpital twice: sinx/(2x)1/2cosx1/2\sin x/(2x) \to 1/2 \cdot \cos x \to 1/2.

  5. Sample 5difficulty 2/5

    Evaluate limx0sinxx\displaystyle\lim_{x\to 0}\dfrac{\sin x}{x} using L'Hôpital.

    • A

      00

    • B

      11

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    • C

      12\tfrac{1}{2}

    • D

      Does not exist

    Why

    0/00/0 form. L'Hôpital: cosx/11\cos x/1 \to 1 at x=0x = 0.