integral of [(2/(1+x^2)) - |x|]

t_reason

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Joined
Sep 7, 2006
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Could you please show me how to solve the integral of
[(2/(1+x^2)) - |x|] ?

I think I need to use u substitution but I'm not sure..
 
\(\displaystyle \L\\2\int\frac{1}{1+x^{2}}dx+\int{|x|}dx\)

Hint:

\(\displaystyle \L\\\frac{d}{dx}[tan^{-1}(x)]=\frac{1}{1+x^{2}}\)


\(\displaystyle \L\\\int{x}dx=\frac{x^{2}}{2}=\frac{(x)(x)}{2}\;\ and\;\ \int{-x}dx=\frac{-x^{2}}{2}=\frac{(-x)(x)}{2}=\)

Therefore,
\(\displaystyle \L\\\int{|x|}dx=\frac{x|x|}{2}\)
 
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