oo / | | 2 | ------------ dx | 2 | x + 4*x + 8 | / 0
Integral(2/(x^2 + 4*x + 8), (x, 0, oo))
/ | | 2 | ------------ dx | 2 | x + 4*x + 8 | /
/2\
|-|
2 \4/
------------ = --------------
2 2
x + 4*x + 8 / x \
|- - - 1| + 1
\ 2 / / | | 2 | ------------ dx | 2 = | x + 4*x + 8 | /
/
|
| 1
| -------------- dx
| 2
| / x \
| |- - - 1| + 1
| \ 2 /
|
/
--------------------
2 /
|
| 1
| -------------- dx
| 2
| / x \
| |- - - 1| + 1
| \ 2 /
|
/
--------------------
2 x
v = -1 - -
2 /
|
| 1
| ------ dv
| 2
| 1 + v
|
/ atan(v)
------------ = -------
2 2 /
|
| 1
| -------------- dx
| 2
| / x \
| |- - - 1| + 1
| \ 2 /
|
/ / x\
-------------------- = atan|1 + -|
2 \ 2/ / x\
C + atan|1 + -|
\ 2// | | 2 / x\ | ------------ dx = C + atan|1 + -| | 2 \ 2/ | x + 4*x + 8 | /
Use the examples entering the upper and lower limits of integration.