Intermediate Value Theorem...2

Discussion in 'Calculus' started by nycmathguy, May 23, 2022.

  1. nycmathguy

    nycmathguy

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    Calculus
    Section 2.5

    Screenshot_20220516-084404_Samsung Notes.jpg

    IMG_20220523_102844.jpg

    Screenshot_20220523-100550_Samsung Internet.jpg
     
    nycmathguy, May 23, 2022
    #1
  2. nycmathguy

    MathLover1

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    giiven: ln(x) =x - √x

    Let f(x) = ln(x) - x + √x

    f is continuous on the interval [2,3].

    f(2) = ln(2) - 2 + √2 > 0

    f(3) = ln(3) - 3 + √3 < 0

    By the Intermediate value Theorem, there is at least one number, c, between 2 and 3 such that f(c) = 0.

    So, ln(c) - c + √c = 0

    Therefore, ln(c )= c + √c


    as you stated above, ln(x)-x+sqrt(x)=0 solutions are

    x = 1
    x≈2.49091

    as you can see on the graph, x≈2.49091 is between 2 and 3
     
    MathLover1, May 23, 2022
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    nycmathguy likes this.
  3. nycmathguy

    nycmathguy

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    I see my error. The x-value(s) found must lie between the given interval not between f(a) and f(b).
     
    nycmathguy, May 23, 2022
    #3
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