Integral of 1/(x(1+x^2)) dx
The solution
Detail solution
-
There are multiple ways to do this integral.
Method #1
-
Rewrite the integrand:
1⋅x(x2+1)1=−x2+1x+x1
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−x2+1x)dx=−∫x2+1xdx
-
The integral of a constant times a function is the constant times the integral of the function:
∫x2+1xdx=2∫x2+12xdx
-
Let u=x2+1.
Then let du=2xdx and substitute 2du:
∫2u1du
-
The integral of u1 is log(u).
Now substitute u back in:
log(x2+1)
So, the result is: 2log(x2+1)
So, the result is: −2log(x2+1)
-
The integral of x1 is log(x).
The result is: log(x)−2log(x2+1)
Method #2
-
Rewrite the integrand:
1⋅x(x2+1)1=x3+x1
-
Rewrite the integrand:
x3+x1=−x2+1x+x1
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−x2+1x)dx=−∫x2+1xdx
-
The integral of a constant times a function is the constant times the integral of the function:
∫x2+1xdx=2∫x2+12xdx
-
Let u=x2+1.
Then let du=2xdx and substitute 2du:
∫2u1du
-
The integral of u1 is log(u).
Now substitute u back in:
log(x2+1)
So, the result is: 2log(x2+1)
So, the result is: −2log(x2+1)
-
The integral of x1 is log(x).
The result is: log(x)−2log(x2+1)
Method #3
-
Rewrite the integrand:
1⋅x(x2+1)1=x3+x1
-
Rewrite the integrand:
x3+x1=−x2+1x+x1
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−x2+1x)dx=−∫x2+1xdx
-
The integral of a constant times a function is the constant times the integral of the function:
∫x2+1xdx=2∫x2+12xdx
-
Let u=x2+1.
Then let du=2xdx and substitute 2du:
∫2u1du
-
The integral of u1 is log(u).
Now substitute u back in:
log(x2+1)
So, the result is: 2log(x2+1)
So, the result is: −2log(x2+1)
-
The integral of x1 is log(x).
The result is: log(x)−2log(x2+1)
-
Add the constant of integration:
log(x)−2log(x2+1)+constant
The answer is:
log(x)−2log(x2+1)+constant
The answer (Indefinite)
[src]
/
| / 2\
| 1 log\1 + x /
| 1*---------- dx = C - ----------- + log(x)
| / 2\ 2
| x*\1 + x /
|
/
logx−2log(x2+1)
Use the examples entering the upper and lower limits of integration.