# Math Help - finding integral of...

1. ## finding integral of...

i can't seem to figure out how to get this integral.
the integrla of (x+1)/(x^2+2x+2)

2. Hello, xslim12!

i can't seem to figure out how to get this integral.

. . $\int \frac{(x+1)\,dx}{x^2+2x+2}$

The answer has $\ln$ in it . . . didn't it make you suspicious?

Let: $u \:=\:x^2 + 2x + 2\quad\Rightarrow\quad du \:=\:(2x + 2)\,dx\quad\Rightarrow\quad (x+1)dx \:=\:\frac{1}{2}du$

Substitute: . $\int\frac{\overbrace{(x+1)\,dx}^{\frac{1}{2}\,du}} {\underbrace{x^2+2x+2}_u} \;=\;\frac{1}{2}\int\frac{du}{u}$ . . . . Got it?

3. Originally Posted by Soroban
Hello, xslim12!

The answer has $\ln$ in it . . . didn't it make you suspicious?

Let: $u \:=\:x^2 + 2x + 2\quad\Rightarrow\quad du \:=\2x + 2)\,dx\quad\Rightarrow\quad (x+1)dx \:=\:\frac{1}{2}du" alt="u \:=\:x^2 + 2x + 2\quad\Rightarrow\quad du \:=\2x + 2)\,dx\quad\Rightarrow\quad (x+1)dx \:=\:\frac{1}{2}du" />

Substitute: . $\int\frac{\overbrace{(x+1)\,dx}^{\frac{1}{2}\,du}} {\underbrace{x^2+2x+2}_u} \;=\;\frac{1}{2}\int\frac{du}{u}$ . . . . Got it?

omg your a life saver. Integration by substitution, i completely forgot about that!
accidentally said by parts LOL :-p
thanks again man