Integral of (1-log(x))/x dx
The solution
Detail solution
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There are multiple ways to do this integral.
Method #1
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Let u=1−log(x).
Then let du=−xdx and substitute −du:
∫(−u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫udu=−∫udu
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The integral of un is n+1un+1 when n=−1:
∫udu=2u2
So, the result is: −2u2
Now substitute u back in:
−2(1−log(x))2
Method #2
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Rewrite the integrand:
x1−log(x)=−xlog(x)−1
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The integral of a constant times a function is the constant times the integral of the function:
∫(−xlog(x)−1)dx=−∫xlog(x)−1dx
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Let u=x1.
Then let du=−x2dx and substitute −du:
∫(−ulog(u1)−1)du
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The integral of a constant times a function is the constant times the integral of the function:
∫ulog(u1)−1du=−∫ulog(u1)−1du
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Let u=log(u1)−1.
Then let du=−udu and substitute −du:
∫(−u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫udu=−∫udu
-
The integral of un is n+1un+1 when n=−1:
∫udu=2u2
So, the result is: −2u2
Now substitute u back in:
−2(log(u1)−1)2
So, the result is: 2(log(u1)−1)2
Now substitute u back in:
2(log(x)−1)2
So, the result is: −2(log(x)−1)2
Method #3
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Rewrite the integrand:
x1−log(x)=−xlog(x)+x1
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Integrate term-by-term:
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The integral of a constant times a function is the constant times the integral of the function:
∫(−xlog(x))dx=−∫xlog(x)dx
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Let u=x1.
Then let du=−x2dx and substitute −du:
∫(−ulog(u1))du
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The integral of a constant times a function is the constant times the integral of the function:
∫ulog(u1)du=−∫ulog(u1)du
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Let u=log(u1).
Then let du=−udu and substitute −du:
∫(−u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫udu=−∫udu
-
The integral of un is n+1un+1 when n=−1:
∫udu=2u2
So, the result is: −2u2
Now substitute u back in:
−2log(u1)2
So, the result is: 2log(u1)2
Now substitute u back in:
2log(x)2
So, the result is: −2log(x)2
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The integral of x1 is log(x).
The result is: −2log(x)2+log(x)
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Now simplify:
−2(log(x)−1)2
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Add the constant of integration:
−2(log(x)−1)2+constant
The answer is:
−2(log(x)−1)2+constant
The answer (Indefinite)
[src]
/
| 2
| 1 - log(x) (1 - log(x))
| ---------- dx = C - -------------
| x 2
|
/
∫x1−log(x)dx=C−2(1−log(x))2
2/ x\
log \e / / x\
- -------- + log\e /
2
−2log(ex)2+log(ex)
=
2/ x\
log \e / / x\
- -------- + log\e /
2
−2log(ex)2+log(ex)
-log(exp(x))^2/2 + log(exp(x))
Use the examples entering the upper and lower limits of integration.