Problem 2-8: Integration

Find  \displaystyle\int \! \frac{e^x}{1+e^x}\, dx.

Solution

Let  u=1+e^x, therefore  du=e^x dx \to dx=\frac{1}{u-1}du. Hence

 \displaystyle\int \! \frac{e^x}{1+e^x}\, dx = \displaystyle\int \! \frac{u-1}{u} \frac{1}{u-1}\,du = \displaystyle\int \! \frac{1}{u} \,du=\ln (u)=\ln(1+e^x)
Problem 2-8

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    Comments

    3 responses to “Problem 2-8: Integration”

    1. jose flaminio tellez abril Avatar
      jose flaminio tellez abril

      aprender a integrar


      _____________
      learned to integrate

    2. yohannes berhanu Avatar
      yohannes berhanu

      i really appreciate if u can send me newsletter every week. i am a pre college student , and i am glad to have this kind of website that would enable me and other fellas to succed on their academic activities.

      1. Dr. Yaz Z. Li Avatar

        Dear Yohannes,

        I am thinking of starting a newsletter. All registered user would be receiving it.

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