Integral of cos(5x)*(cos(2x))^2 dx
The solution
Detail solution
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Rewrite the integrand:
cos2(2x)cos(5x)=64cos9(x)−144cos7(x)+116cos5(x)−40cos3(x)+5cos(x)
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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:
∫64cos9(x)dx=64∫cos9(x)dx
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Rewrite the integrand:
cos9(x)=(1−sin2(x))4cos(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))4cos(x)=sin8(x)cos(x)−4sin6(x)cos(x)+6sin4(x)cos(x)−4sin2(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:
∫u8du
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The integral of un is n+1un+1 when n=−1:
∫u8du=9u9
Now substitute u back in:
9sin9(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−4sin6(x)cos(x))dx=−4∫sin6(x)cos(x)dx
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Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u6du
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The integral of un is n+1un+1 when n=−1:
∫u6du=7u7
Now substitute u back in:
7sin7(x)
So, the result is: −74sin7(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫6sin4(x)cos(x)dx=6∫sin4(x)cos(x)dx
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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)
So, the result is: 56sin5(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−4sin2(x)cos(x))dx=−4∫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: −34sin3(x)
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The integral of cosine is sine:
∫cos(x)dx=sin(x)
The result is: 9sin9(x)−74sin7(x)+56sin5(x)−34sin3(x)+sin(x)
Method #2
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Rewrite the integrand:
(1−sin2(x))4cos(x)=sin8(x)cos(x)−4sin6(x)cos(x)+6sin4(x)cos(x)−4sin2(x)cos(x)+cos(x)
-
Integrate term-by-term:
-
Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u8du
-
The integral of un is n+1un+1 when n=−1:
∫u8du=9u9
Now substitute u back in:
9sin9(x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−4sin6(x)cos(x))dx=−4∫sin6(x)cos(x)dx
-
Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u6du
-
The integral of un is n+1un+1 when n=−1:
∫u6du=7u7
Now substitute u back in:
7sin7(x)
So, the result is: −74sin7(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫6sin4(x)cos(x)dx=6∫sin4(x)cos(x)dx
-
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)
So, the result is: 56sin5(x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−4sin2(x)cos(x))dx=−4∫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: −34sin3(x)
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The integral of cosine is sine:
∫cos(x)dx=sin(x)
The result is: 9sin9(x)−74sin7(x)+56sin5(x)−34sin3(x)+sin(x)
So, the result is: 964sin9(x)−7256sin7(x)+5384sin5(x)−3256sin3(x)+64sin(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−144cos7(x))dx=−144∫cos7(x)dx
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Rewrite the integrand:
cos7(x)=(1−sin2(x))3cos(x)
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Rewrite the integrand:
(1−sin2(x))3cos(x)=−sin6(x)cos(x)+3sin4(x)cos(x)−3sin2(x)cos(x)+cos(x)
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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:
∫(−sin6(x)cos(x))dx=−∫sin6(x)cos(x)dx
-
Let u=sin(x).
Then let du=cos(x)dx and substitute du:
∫u6du
-
The integral of un is n+1un+1 when n=−1:
∫u6du=7u7
Now substitute u back in:
7sin7(x)
So, the result is: −7sin7(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫3sin4(x)cos(x)dx=3∫sin4(x)cos(x)dx
-
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)
So, the result is: 53sin5(x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−3sin2(x)cos(x))dx=−3∫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: −sin3(x)
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The integral of cosine is sine:
∫cos(x)dx=sin(x)
The result is: −7sin7(x)+53sin5(x)−sin3(x)+sin(x)
So, the result is: 7144sin7(x)−5432sin5(x)+144sin3(x)−144sin(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫116cos5(x)dx=116∫cos5(x)dx
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Rewrite the integrand:
cos5(x)=(1−sin2(x))2cos(x)
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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:
-
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
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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)
So, the result is: 5116sin5(x)−3232sin3(x)+116sin(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−40cos3(x))dx=−40∫cos3(x)dx
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Rewrite the integrand:
cos3(x)=(1−sin2(x))cos(x)
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Let u=sin(x).
Then let du=cos(x)dx 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(x)+sin(x)
So, the result is: 340sin3(x)−40sin(x)
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The integral of a constant times a function is the constant times the integral of the function:
∫5cos(x)dx=5∫cos(x)dx
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The integral of cosine is sine:
∫cos(x)dx=sin(x)
So, the result is: 5sin(x)
The result is: 964sin9(x)−16sin7(x)+568sin5(x)−316sin3(x)+sin(x)
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Now simplify:
45(320sin8(x)−720sin6(x)+612sin4(x)−240sin2(x)+45)sin(x)
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Add the constant of integration:
45(320sin8(x)−720sin6(x)+612sin4(x)−240sin2(x)+45)sin(x)+constant
The answer is:
45(320sin8(x)−720sin6(x)+612sin4(x)−240sin2(x)+45)sin(x)+constant
The answer (Indefinite)
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| 3 9 5
| 2 7 16*sin (x) 64*sin (x) 68*sin (x)
| cos(5*x)*cos (2*x) dx = C - 16*sin (x) - ---------- + ---------- + ---------- + sin(x)
| 3 9 5
/
∫cos2(2x)cos(5x)dx=C+964sin9(x)−16sin7(x)+568sin5(x)−316sin3(x)+sin(x)
The graph
Use the examples entering the upper and lower limits of integration.