Integral of sin^5x/cosx dx
The solution
Detail solution
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Rewrite the integrand:
cos(x)sin5(x)=cos(x)(1−cos2(x))2sin(x)
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There are multiple ways to do this integral.
Method #1
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Let u=cos2(x).
Then let du=−2sin(x)cos(x)dx and substitute −2du:
∫(−2uu2−2u+1)du
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The integral of a constant times a function is the constant times the integral of the function:
∫uu2−2u+1du=−2∫uu2−2u+1du
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Rewrite the integrand:
uu2−2u+1=u−2+u1
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Integrate term-by-term:
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The integral of un is n+1un+1 when n=−1:
∫udu=2u2
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The integral of a constant is the constant times the variable of integration:
∫(−2)du=−2u
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The integral of u1 is log(u).
The result is: 2u2−2u+log(u)
So, the result is: −4u2+u−2log(u)
Now substitute u back in:
−2log(cos2(x))−4cos4(x)+cos2(x)
Method #2
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Rewrite the integrand:
cos(x)(1−cos2(x))2sin(x)=cos(x)sin(x)cos4(x)−2sin(x)cos2(x)+sin(x)
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Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫(−uu4−2u2+1)du
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The integral of a constant times a function is the constant times the integral of the function:
∫uu4−2u2+1du=−∫uu4−2u2+1du
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Let u=u2.
Then let du=2udu and substitute 2du:
∫2uu2−2u+1du
-
The integral of a constant times a function is the constant times the integral of the function:
∫uu2−2u+1du=2∫uu2−2u+1du
-
Rewrite the integrand:
uu2−2u+1=u−2+u1
-
Integrate term-by-term:
-
The integral of un is n+1un+1 when n=−1:
∫udu=2u2
-
The integral of a constant is the constant times the variable of integration:
∫(−2)du=−2u
-
The integral of u1 is log(u).
The result is: 2u2−2u+log(u)
So, the result is: 4u2−u+2log(u)
Now substitute u back in:
4u4−u2+2log(u2)
So, the result is: −4u4+u2−2log(u2)
Now substitute u back in:
−2log(cos2(x))−4cos4(x)+cos2(x)
Method #3
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Rewrite the integrand:
cos(x)(1−cos2(x))2sin(x)=sin(x)cos3(x)−2sin(x)cos(x)+cos(x)sin(x)
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Integrate term-by-term:
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Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫(−u3)du
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The integral of a constant times a function is the constant times the integral of the function:
∫u3du=−∫u3du
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The integral of un is n+1un+1 when n=−1:
∫u3du=4u4
So, the result is: −4u4
Now substitute u back in:
−4cos4(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−2sin(x)cos(x))dx=−2∫sin(x)cos(x)dx
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Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫(−u)du
-
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:
−2cos2(x)
So, the result is: cos2(x)
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Let u=cos(x).
Then let du=−sin(x)dx 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 u1 is log(u).
So, the result is: −log(u)
Now substitute u back in:
−log(cos(x))
The result is: −log(cos(x))−4cos4(x)+cos2(x)
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Add the constant of integration:
−2log(cos2(x))−4cos4(x)+cos2(x)+constant
The answer is:
−2log(cos2(x))−4cos4(x)+cos2(x)+constant
The answer (Indefinite)
[src]
/
|
| 5 / 2 \ 4
| sin (x) 2 log\cos (x)/ cos (x)
| ------- dx = C + cos (x) - ------------ - -------
| cos(x) 2 4
|
/
∫cos(x)sin5(x)dx=C−2log(cos2(x))−4cos4(x)+cos2(x)
The graph
4
3 2 cos (1)
- - + cos (1) - log(cos(1)) - -------
4 4
−43−4cos4(1)+cos2(1)−log(cos(1))
=
4
3 2 cos (1)
- - + cos (1) - log(cos(1)) - -------
4 4
−43−4cos4(1)+cos2(1)−log(cos(1))
-3/4 + cos(1)^2 - log(cos(1)) - cos(1)^4/4
Use the examples entering the upper and lower limits of integration.