Integral of sin³xcos²x dx
The solution
Detail solution
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Rewrite the integrand:
sin3(x)cos2(x)=(1−cos2(x))sin(x)cos2(x)
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There are multiple ways to do this integral.
Method #1
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Let u=cos(x).
Then let du=−sin(x)dx and substitute du:
∫(u4−u2)du
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Integrate term-by-term:
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The integral of un is n+1un+1 when n=−1:
∫u4du=5u5
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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: 5u5−3u3
Now substitute u back in:
5cos5(x)−3cos3(x)
Method #2
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Rewrite the integrand:
(1−cos2(x))sin(x)cos2(x)=−sin(x)cos4(x)+sin(x)cos2(x)
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Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−sin(x)cos4(x))dx=−∫sin(x)cos4(x)dx
-
Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫u4du
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−u4)du=−∫u4du
-
The integral of un is n+1un+1 when n=−1:
∫u4du=5u5
So, the result is: −5u5
Now substitute u back in:
−5cos5(x)
So, the result is: 5cos5(x)
-
Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫u2du
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−u2)du=−∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −3u3
Now substitute u back in:
−3cos3(x)
The result is: 5cos5(x)−3cos3(x)
Method #3
-
Rewrite the integrand:
(1−cos2(x))sin(x)cos2(x)=−sin(x)cos4(x)+sin(x)cos2(x)
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−sin(x)cos4(x))dx=−∫sin(x)cos4(x)dx
-
Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫u4du
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−u4)du=−∫u4du
-
The integral of un is n+1un+1 when n=−1:
∫u4du=5u5
So, the result is: −5u5
Now substitute u back in:
−5cos5(x)
So, the result is: 5cos5(x)
-
Let u=cos(x).
Then let du=−sin(x)dx and substitute −du:
∫u2du
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−u2)du=−∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −3u3
Now substitute u back in:
−3cos3(x)
The result is: 5cos5(x)−3cos3(x)
-
Add the constant of integration:
5cos5(x)−3cos3(x)+constant
The answer is:
5cos5(x)−3cos3(x)+constant
The answer (Indefinite)
[src]
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| 3 5
| 3 2 cos (x) cos (x)
| sin (x)*cos (x) dx = C - ------- + -------
| 3 5
/
153cos5x−5cos3x
The graph
3 5
2 cos (1) cos (1)
-- - ------- + -------
15 3 5
153cos51−5cos31+152
=
3 5
2 cos (1) cos (1)
-- - ------- + -------
15 3 5
−3cos3(1)+5cos5(1)+152
Use the examples entering the upper and lower limits of integration.