Indefinite integral substitution

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SUMMARY

The discussion focuses on evaluating the indefinite integral of the function \(\frac{e^x}{e^x + 1}\) with respect to \(x\). The user initially substituted \(u = e^x + 1\), leading to \(du = e^x dx\), which transformed the integral into \(\int u^{-1} du\). However, the correct antiderivative is \(\ln|e^x + 1| + C\), as it follows the form \(\int \frac{du}{u}\). This highlights the importance of correctly identifying the form of the integral during substitution.

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  • Understanding of indefinite integrals
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  • Knowledge of logarithmic functions and their properties
  • Basic calculus concepts, including differentiation and integration
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evaluate the indefinite integral ((e^x)/((e^x)+1))dx

I let u = ((e^x)+1)

then

du = (e^x)dx

which occurs in the original equation so..

indefinite ingegral ((u^-1)du)

taking the antiderivative I get 1 + C

is this right? thanks!
 
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\int \frac{e^{x}}{e^{x}+1} dx

it should be \ln|e^{x}+1| + C because it is of the form \int \frac{du}{u}
 
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