Integral of arctan dx
The solution
Detail solution
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=atan(x) and let dv(x)=1.
Then du(x)=x2+11.
To find v(x):
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The integral of a constant is the constant times the variable of integration:
∫1dx=x
Now evaluate the sub-integral.
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The integral of a constant times a function is the constant times the integral of the function:
∫x2+1xdx=2∫x2+12xdx
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Let u=x2+1.
Then let du=2xdx and substitute 2du:
∫2u1du
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The integral of u1 is log(u).
Now substitute u back in:
log(x2+1)
So, the result is: 2log(x2+1)
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Add the constant of integration:
xatan(x)−2log(x2+1)+constant
The answer is:
xatan(x)−2log(x2+1)+constant
The answer (Indefinite)
[src]
/ / 2\
| log\1 + x /
| atan(x) dx = C - ----------- + x*atan(x)
| 2
/
∫atan(x)dx=C+xatan(x)−2log(x2+1)
The graph
log(2) pi
- ------ + --
2 4
−2log(2)+4π
=
log(2) pi
- ------ + --
2 4
−2log(2)+4π
Use the examples entering the upper and lower limits of integration.