Integral of cos^5(x) dx
The solution
Detail solution
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Rewrite the integrand:
cos5(x)=(1−sin2(x))2cos(x)
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There are multiple ways to do this integral.
Method #1
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Rewrite the integrand:
(1−sin2(x))2cos(x)=sin4(x)cos(x)−2sin2(x)cos(x)+cos(x)
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Integrate term-by-term:
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Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u4du
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The integral of un is n+1un+1 when n=−1:
∫u4du=5u5
Now substitute u back in:
5sin5(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−2sin2(x)cos(x))dx=−2∫sin2(x)cos(x)dx
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Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u2du
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The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
Now substitute u back in:
3sin3(x)
So, the result is: −32sin3(x)
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The integral of cosine is sine:
∫cos(x)dx=sin(x)
The result is: 5sin5(x)−32sin3(x)+sin(x)
Method #2
-
Rewrite the integrand:
(1−sin2(x))2cos(x)=sin4(x)cos(x)−2sin2(x)cos(x)+cos(x)
-
Integrate term-by-term:
-
Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u4du
-
The integral of un is n+1un+1 when n=−1:
∫u4du=5u5
Now substitute u back in:
5sin5(x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−2sin2(x)cos(x))dx=−2∫sin2(x)cos(x)dx
-
Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
Now substitute u back in:
3sin3(x)
So, the result is: −32sin3(x)
-
The integral of cosine is sine:
∫cos(x)dx=sin(x)
The result is: 5sin5(x)−32sin3(x)+sin(x)
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Add the constant of integration:
5sin5(x)−32sin3(x)+sin(x)+constant
The answer is:
5sin5(x)−32sin3(x)+sin(x)+constant
The answer (Indefinite)
[src]
/
| 3 5
| 5 2*sin (x) sin (x)
| cos (x) dx = C - --------- + ------- + sin(x)
| 3 5
/
∫cos5(x)dx=C+5sin5(x)−32sin3(x)+sin(x)
The graph
3 5
2*sin (1) sin (1)
- --------- + ------- + sin(1)
3 5
−32sin3(1)+5sin5(1)+sin(1)
=
3 5
2*sin (1) sin (1)
- --------- + ------- + sin(1)
3 5
−32sin3(1)+5sin5(1)+sin(1)
-2*sin(1)^3/3 + sin(1)^5/5 + sin(1)
Use the examples entering the upper and lower limits of integration.