Integral of tan((pi)(x)/2) dx
The solution
Detail solution
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Rewrite the integrand:
tan(2πx)=cos(2πx)sin(2πx)
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There are multiple ways to do this integral.
Method #1
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Let u=cos(2πx).
Then let du=−2πsin(2πx)dx and substitute −π2du:
∫π2u4du
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The integral of a constant times a function is the constant times the integral of the function:
∫(−uπ2)du=−π2∫u1du
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The integral of u1 is log(u).
So, the result is: −π2log(u)
Now substitute u back in:
−π2log(cos(2πx))
Method #2
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Let u=2πx.
Then let du=2πdx and substitute π2du:
∫π2cos(u)4sin(u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫πcos(u)2sin(u)du=π2∫cos(u)sin(u)du
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Let u=cos(u).
Then let du=−sin(u)du and substitute −du:
∫u1du
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The integral of a constant times a function is the constant times the integral of the function:
∫(−u1)du=−∫u1du
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The integral of u1 is log(u).
So, the result is: −log(u)
Now substitute u back in:
−log(cos(u))
So, the result is: −π2log(cos(u))
Now substitute u back in:
−π2log(cos(2πx))
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Add the constant of integration:
−π2log(cos(2πx))+constant
The answer is:
−π2log(cos(2πx))+constant
The answer (Indefinite)
[src]
/ / /pi*x\\
| 2*log|cos|----||
| /pi*x\ \ \ 2 //
| tan|----| dx = C - ----------------
| \ 2 / pi
|
/
π2logsec(2πx)
The graph
−π2logcos(2π)
=
Use the examples entering the upper and lower limits of integration.