Integral of (lnxdx)/(x(1+lnx)^1/2) 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=log(x).
Then let du=xdx and substitute du:
∫u+1udu
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Let u=u+11.
Then let du=−2(u+1)23du and substitute du:
∫(−2(−1+u21)2+2−u22)du
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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:
∫(−2(−1+u21)2)du=−2∫(−1+u21)2du
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There are multiple ways to do this integral.
Method #1
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Rewrite the integrand:
(−1+u21)2=1−u22+u41
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Integrate term-by-term:
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The integral of a constant is the constant times the variable of integration:
∫1du=u
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The integral of a constant times a function is the constant times the integral of the function:
∫(−u22)du=−2∫u21du
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The integral of un is n+1un+1 when n=−1:
∫u21du=−u1
So, the result is: u2
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The integral of un is n+1un+1 when n=−1:
∫u41du=−3u31
The result is: u+u2−3u31
Method #2
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Rewrite the integrand:
(−1+u21)2=u4u4−2u2+1
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Rewrite the integrand:
u4u4−2u2+1=1−u22+u41
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Integrate term-by-term:
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The integral of a constant is the constant times the variable of integration:
∫1du=u
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−u22)du=−2∫u21du
-
The integral of un is n+1un+1 when n=−1:
∫u21du=−u1
So, the result is: u2
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The integral of un is n+1un+1 when n=−1:
∫u41du=−3u31
The result is: u+u2−3u31
So, the result is: −2u−u4+3u32
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The integral of a constant is the constant times the variable of integration:
∫2du=2u
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The integral of a constant times a function is the constant times the integral of the function:
∫(−u22)du=−2∫u21du
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The integral of un is n+1un+1 when n=−1:
∫u21du=−u1
So, the result is: u2
The result is: −u2+3u32
Now substitute u back in:
32(u+1)23−2u+1
Now substitute u back in:
32(log(x)+1)23−2log(x)+1
Method #2
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=log(x) and let dv(x)=xlog(x)+11.
Then du(x)=x1.
To find v(x):
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Let u=x1.
Then let du=−x2dx and substitute −du:
∫−ulog(u1)+11du
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The integral of a constant times a function is the constant times the integral of the function:
∫ulog(u1)+11du=−∫ulog(u1)+11du
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Let u=log(u1)+1.
Then let du=−udu and substitute −du:
∫(−u1)du
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The integral of a constant times a function is the constant times the integral of the function:
∫u1du=−∫u1du
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The integral of un is n+1un+1 when n=−1:
∫u1du=2u
So, the result is: −2u
Now substitute u back in:
−2log(u1)+1
So, the result is: 2log(u1)+1
Now substitute u back in:
2log(x)+1
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:
∫x2log(x)+1dx=2∫xlog(x)+1dx
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Let u=x1.
Then let du=−x2dx and substitute −du:
∫−ulog(u1)+1du
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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
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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=32u23
So, the result is: −32u23
Now substitute u back in:
−32(log(u1)+1)23
So, the result is: 32(log(u1)+1)23
Now substitute u back in:
32(log(x)+1)23
So, the result is: 34(log(x)+1)23
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Now simplify:
32(log(x)−2)log(x)+1
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Add the constant of integration:
32(log(x)−2)log(x)+1+constant
The answer is:
32(log(x)−2)log(x)+1+constant
The answer (Indefinite)
[src]
/
| 3/2
| log(x) ____________ 2*(1 + log(x))
| ---------------- dx = C - 2*\/ 1 + log(x) + -----------------
| ____________ 3
| x*\/ 1 + log(x)
|
/
∫xlog(x)+1log(x)dx=C+32(log(x)+1)23−2log(x)+1
The graph
−34+∞i
=
−34+∞i
(-1.0818887836703 + 202.533724926781j)
(-1.0818887836703 + 202.533724926781j)
Use the examples entering the upper and lower limits of integration.