Integral of (-log(x))/x^2 dx
The solution
Detail solution
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Let u=log(x).
Then let du=xdx and substitute −du:
∫(−ue−u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫ue−udu=−∫ue−udu
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There are multiple ways to do this integral.
Method #1
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Let u=−u.
Then let du=−du and substitute du:
∫ueudu
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Use integration by parts:
∫udv=uv−∫vdu
Let u(u)=u and let dv(u)=eu.
Then du(u)=1.
To find v(u):
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The integral of the exponential function is itself.
∫eudu=eu
Now evaluate the sub-integral.
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The integral of the exponential function is itself.
∫eudu=eu
Now substitute u back in:
−ue−u−e−u
Method #2
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Use integration by parts:
∫udv=uv−∫vdu
Let u(u)=u and let dv(u)=e−u.
Then du(u)=1.
To find v(u):
-
Let u=−u.
Then let du=−du and substitute −du:
∫(−eu)du
-
The integral of a constant times a function is the constant times the integral of the function:
-
The integral of the exponential function is itself.
∫eudu=eu
So, the result is: −eu
Now substitute u back in:
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:
∫(−e−u)du=−∫e−udu
-
Let u=−u.
Then let du=−du and substitute −du:
∫(−eu)du
-
The integral of a constant times a function is the constant times the integral of the function:
-
The integral of the exponential function is itself.
∫eudu=eu
So, the result is: −eu
Now substitute u back in:
So, the result is: e−u
So, the result is: ue−u+e−u
Now substitute u back in:
xlog(x)+x1
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Now simplify:
xlog(x)+1
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Add the constant of integration:
xlog(x)+1+constant
The answer is:
xlog(x)+1+constant
The answer (Indefinite)
[src]
/
|
| -log(x) 1 log(x)
| -------- dx = C + - + ------
| 2 x x
| x
|
/
∫x2(−1)log(x)dx=C+xlog(x)+x1
Use the examples entering the upper and lower limits of integration.