Integral of sin(log2x)/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=log(2x).
Then let du=xdx and substitute du:
∫sin(u)du
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The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
Now substitute u back in:
−cos(log(2x))
Method #2
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Rewrite the integrand:
xsin(log(2x))=xsin(log(x)+log(2))
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Let u=x1.
Then let du=−x2dx and substitute −du:
∫usin(log(u1)+log(2))du
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The integral of a constant times a function is the constant times the integral of the function:
∫(−usin(log(u1)+log(2)))du=−∫usin(log(u1)+log(2))du
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Let u=log(u1)+log(2).
Then let du=−udu and substitute −du:
∫sin(u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫(−sin(u))du=−∫sin(u)du
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The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: cos(u)
Now substitute u back in:
cos(log(u1)+log(2))
So, the result is: −cos(log(u1)+log(2))
Now substitute u back in:
−cos(log(x)+log(2))
Method #3
-
Rewrite the integrand:
xsin(log(2x))=xsin(log(x)+log(2))
-
Let u=x1.
Then let du=−x2dx and substitute −du:
∫usin(log(u1)+log(2))du
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−usin(log(u1)+log(2)))du=−∫usin(log(u1)+log(2))du
-
Let u=log(u1)+log(2).
Then let du=−udu and substitute −du:
∫sin(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−sin(u))du=−∫sin(u)du
-
The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: cos(u)
Now substitute u back in:
cos(log(u1)+log(2))
So, the result is: −cos(log(u1)+log(2))
Now substitute u back in:
−cos(log(x)+log(2))
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Add the constant of integration:
−cos(log(2x))+constant
The answer is:
−cos(log(2x))+constant
The answer (Indefinite)
[src]
/
|
| sin(log(2*x))
| ------------- dx = C - cos(log(2*x))
| x
|
/
−coslog(2x)
<-1 - cos(log(2)), 1 - cos(log(2))>
∫01xsinlog(2x)dx
=
<-1 - cos(log(2)), 1 - cos(log(2))>
⟨−1−cos(log(2)),−cos(log(2))+1⟩
Use the examples entering the upper and lower limits of integration.