Need help with how to do this integral

G

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The integral of 1/(e^x+e^-x) with respect to x(ie.dx)

thank you in advance[/tex]
 
Does it help you in knowing that \(\displaystyle \L\\\frac{1}{e^{x}+e^{-x}}=\frac{1}

{2}sech(x)\)

Probably not, huh?.

\(\displaystyle \L\\\int\frac{1}{e^{x}+e^{-x}}dx\)

Factor \(\displaystyle \L\\e^{x}\) out of the denominator:

\(\displaystyle \L\\\int\frac{1}{e^{x}(1+e^{-2x})}dx\)

Let \(\displaystyle \L\\u=-e^{-x};\;\ du=e^{-x}dx=\frac{1}{e^{x}}dx\)

\(\displaystyle \L\\\int\frac{1}{1+u^{2}}du\)
 
\(\displaystyle \L \frac{1}{e^x + e^{-x}} =\)

\(\displaystyle \L \frac{1}{\frac{e^{2x}}{e^x} + \frac{1}{e^x}} =\)

\(\displaystyle \L \frac{1}{\frac{e^{2x} + 1}{e^x}} =\)

\(\displaystyle \L \frac{e^x}{e^{2x} + 1}\)

\(\displaystyle \L \int \frac{e^x}{e^{2x} + 1} dx = arctan(e^x) + C\)
 
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