Solve Exponential Equations

Discussion in 'Other Pre-University Math' started by nycmathguy, Oct 22, 2021.

  1. nycmathguy

    nycmathguy

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    Section 3.4
    20, 32, 42

    20211021_222111.jpg

    20211022_104422.jpg

    20211022_104749.jpg

    20211022_105952.jpg
     
    nycmathguy, Oct 22, 2021
    #1
  2. nycmathguy

    MathLover1

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    20. correct but second line is not needed

    32.
    500e^(-2x)=125

    e^(-2x)=125/500

    e^(-2x)=1/4

    e^(-2x)=4^-2......4^-2=2^-4

    ln(e^(-2x))=ln(2^-4)

    (-2x)ln(e)=-4ln(2)..............ln(e)=1

    -2x=-4ln(2)

    x=-4ln(2)/-2

    x=2ln(2)-> exact solution

    x ≈ 1.38629 -> approximate solution

    42. correct
     
    MathLover1, Oct 22, 2021
    #2
    nycmathguy likes this.
  3. nycmathguy

    nycmathguy

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    Well, 2/3 is not too bad. We start trigonometry next week in Chapter 4.
     
    nycmathguy, Oct 23, 2021
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