Need help integrating

kluda06

New member
Joined
Apr 28, 2013
Messages
12
⌠(2x-5)/(x2+2x+2) dx

i used u substitution

u=
x2+2x+2
du=2x+2dx
du/2x+2=dx

after plugging in dx i ended up getting

-(5/2)⌠1/(x2+2x+2) = -(5/2)Ln |x2+2x+2|

however the answer is ln|x2+2x+2|-7arctan (x+1)+C

What am I doing wrong? please help!
 
I would rewrite the integrand as follows:

\(\displaystyle \dfrac{2x-5}{x^2+2x+2}=\dfrac{(2x+2)-7}{x^2+2x+2}=\dfrac{2x+2}{x^2+2x+2}-\dfrac{7}{(x+1)^2+1^2}\)
 
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