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

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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