Integral of sin^4(x)cos^2(x) dx
The solution
Detail solution
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Rewrite the integrand:
sin4(x)cos2(x)=(21−2cos(2x))2(2cos(2x)+21)
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There are multiple ways to do this integral.
Method #1
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Let u=2x.
Then let du=2dx and substitute du:
∫(16cos3(u)−16cos2(u)−16cos(u)+161)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:
∫16cos3(u)du=16∫cos3(u)du
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Rewrite the integrand:
cos3(u)=(1−sin2(u))cos(u)
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Let u=sin(u).
Then let du=cos(u)du and substitute du:
∫(1−u2)du
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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:
∫(−u2)du=−∫u2du
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The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −3u3
The result is: −3u3+u
Now substitute u back in:
−3sin3(u)+sin(u)
So, the result is: −48sin3(u)+16sin(u)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−16cos2(u))du=−16∫cos2(u)du
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Rewrite the integrand:
cos2(u)=2cos(2u)+21
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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:
∫2cos(2u)du=2∫cos(2u)du
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Let u=2u.
Then let du=2du and substitute 2du:
∫4cos(u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫2cos(u)du=2∫cos(u)du
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The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 2sin(u)
Now substitute u back in:
2sin(2u)
So, the result is: 4sin(2u)
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The integral of a constant is the constant times the variable of integration:
∫21du=2u
The result is: 2u+4sin(2u)
So, the result is: −32u−64sin(2u)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−16cos(u))du=−16∫cos(u)du
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The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: −16sin(u)
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The integral of a constant is the constant times the variable of integration:
∫161du=16u
The result is: 32u−64sin(2u)−48sin3(u)
Now substitute u back in:
16x−48sin3(2x)−64sin(4x)
Method #2
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Rewrite the integrand:
(21−2cos(2x))2(2cos(2x)+21)=8cos3(2x)−8cos2(2x)−8cos(2x)+81
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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:
∫8cos3(2x)dx=8∫cos3(2x)dx
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Rewrite the integrand:
cos3(2x)=(1−sin2(2x))cos(2x)
-
Let u=sin(2x).
Then let du=2cos(2x)dx and substitute du:
∫(21−2u2)du
-
Integrate term-by-term:
-
The integral of a constant is the constant times the variable of integration:
∫21du=2u
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−2u2)du=−2∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −6u3
The result is: −6u3+2u
Now substitute u back in:
−6sin3(2x)+2sin(2x)
So, the result is: −48sin3(2x)+16sin(2x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−8cos2(2x))dx=−8∫cos2(2x)dx
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Rewrite the integrand:
cos2(2x)=2cos(4x)+21
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫2cos(4x)dx=2∫cos(4x)dx
-
Let u=4x.
Then let du=4dx and substitute 4du:
∫16cos(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫4cos(u)du=4∫cos(u)du
-
The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 4sin(u)
Now substitute u back in:
4sin(4x)
So, the result is: 8sin(4x)
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The integral of a constant is the constant times the variable of integration:
∫21dx=2x
The result is: 2x+8sin(4x)
So, the result is: −16x−64sin(4x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−8cos(2x))dx=−8∫cos(2x)dx
-
Let u=2x.
Then let du=2dx and substitute 2du:
∫4cos(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫2cos(u)du=2∫cos(u)du
-
The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 2sin(u)
Now substitute u back in:
2sin(2x)
So, the result is: −16sin(2x)
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The integral of a constant is the constant times the variable of integration:
∫81dx=8x
The result is: 16x−48sin3(2x)−64sin(4x)
Method #3
-
Rewrite the integrand:
(21−2cos(2x))2(2cos(2x)+21)=8cos3(2x)−8cos2(2x)−8cos(2x)+81
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫8cos3(2x)dx=8∫cos3(2x)dx
-
Rewrite the integrand:
cos3(2x)=(1−sin2(2x))cos(2x)
-
Let u=sin(2x).
Then let du=2cos(2x)dx and substitute du:
∫(21−2u2)du
-
Integrate term-by-term:
-
The integral of a constant is the constant times the variable of integration:
∫21du=2u
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−2u2)du=−2∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −6u3
The result is: −6u3+2u
Now substitute u back in:
−6sin3(2x)+2sin(2x)
So, the result is: −48sin3(2x)+16sin(2x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−8cos2(2x))dx=−8∫cos2(2x)dx
-
Rewrite the integrand:
cos2(2x)=2cos(4x)+21
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫2cos(4x)dx=2∫cos(4x)dx
-
Let u=4x.
Then let du=4dx and substitute 4du:
∫16cos(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫4cos(u)du=4∫cos(u)du
-
The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 4sin(u)
Now substitute u back in:
4sin(4x)
So, the result is: 8sin(4x)
-
The integral of a constant is the constant times the variable of integration:
∫21dx=2x
The result is: 2x+8sin(4x)
So, the result is: −16x−64sin(4x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−8cos(2x))dx=−8∫cos(2x)dx
-
Let u=2x.
Then let du=2dx and substitute 2du:
∫4cos(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫2cos(u)du=2∫cos(u)du
-
The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 2sin(u)
Now substitute u back in:
2sin(2x)
So, the result is: −16sin(2x)
-
The integral of a constant is the constant times the variable of integration:
∫81dx=8x
The result is: 16x−48sin3(2x)−64sin(4x)
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Add the constant of integration:
16x−48sin3(2x)−64sin(4x)+constant
The answer is:
16x−48sin3(2x)−64sin(4x)+constant
The answer (Indefinite)
[src]
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| 3
| 4 2 sin (2*x) sin(4*x) x
| sin (x)*cos (x) dx = C - --------- - -------- + --
| 48 64 16
/
842x−2sin(4x)−6sin3(2x)
The graph
3 5
1 cos(1)*sin(1) sin (1)*cos(1) sin (1)*cos(1)
-- - ------------- - -------------- + --------------
16 16 24 6
−1923sin4+4sin32−12
=
3 5
1 cos(1)*sin(1) sin (1)*cos(1) sin (1)*cos(1)
-- - ------------- - -------------- + --------------
16 16 24 6
−16sin(1)cos(1)−24sin3(1)cos(1)+6sin5(1)cos(1)+161
Use the examples entering the upper and lower limits of integration.