Integral of (8x-1)sin(5x+3) dx
The solution
Detail solution
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There are multiple ways to do this integral.
Method #1
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Rewrite the integrand:
(8x−1)sin(5x+3)=8xsin(5x+3)−sin(5x+3)
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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:
∫8xsin(5x+3)dx=8∫xsin(5x+3)dx
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=x and let dv(x)=sin(5x+3).
Then du(x)=1.
To find v(x):
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5sin(u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫sin(u)du=5∫sin(u)du
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The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: −5cos(u)
Now substitute u back in:
−5cos(5x+3)
Now evaluate the sub-integral.
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The integral of a constant times a function is the constant times the integral of the function:
∫(−5cos(5x+3))dx=−5∫cos(5x+3)dx
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Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5cos(u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫cos(u)du=5∫cos(u)du
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The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 5sin(u)
Now substitute u back in:
5sin(5x+3)
So, the result is: −25sin(5x+3)
So, the result is: −58xcos(5x+3)+258sin(5x+3)
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The integral of a constant times a function is the constant times the integral of the function:
∫(−sin(5x+3))dx=−∫sin(5x+3)dx
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5sin(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫sin(u)du=5∫sin(u)du
-
The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: −5cos(u)
Now substitute u back in:
−5cos(5x+3)
So, the result is: 5cos(5x+3)
The result is: −58xcos(5x+3)+258sin(5x+3)+5cos(5x+3)
Method #2
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=8x−1 and let dv(x)=sin(5x+3).
Then du(x)=8.
To find v(x):
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5sin(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫sin(u)du=5∫sin(u)du
-
The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: −5cos(u)
Now substitute u back in:
−5cos(5x+3)
Now evaluate the sub-integral.
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−58cos(5x+3))dx=−58∫cos(5x+3)dx
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5cos(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫cos(u)du=5∫cos(u)du
-
The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 5sin(u)
Now substitute u back in:
5sin(5x+3)
So, the result is: −258sin(5x+3)
Method #3
-
Rewrite the integrand:
(8x−1)sin(5x+3)=8xsin(5x+3)−sin(5x+3)
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫8xsin(5x+3)dx=8∫xsin(5x+3)dx
-
Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=x and let dv(x)=sin(5x+3).
Then du(x)=1.
To find v(x):
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5sin(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫sin(u)du=5∫sin(u)du
-
The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: −5cos(u)
Now substitute u back in:
−5cos(5x+3)
Now evaluate the sub-integral.
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−5cos(5x+3))dx=−5∫cos(5x+3)dx
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5cos(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫cos(u)du=5∫cos(u)du
-
The integral of cosine is sine:
∫cos(u)du=sin(u)
So, the result is: 5sin(u)
Now substitute u back in:
5sin(5x+3)
So, the result is: −25sin(5x+3)
So, the result is: −58xcos(5x+3)+258sin(5x+3)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−sin(5x+3))dx=−∫sin(5x+3)dx
-
Let u=5x+3.
Then let du=5dx and substitute 5du:
∫5sin(u)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫sin(u)du=5∫sin(u)du
-
The integral of sine is negative cosine:
∫sin(u)du=−cos(u)
So, the result is: −5cos(u)
Now substitute u back in:
−5cos(5x+3)
So, the result is: 5cos(5x+3)
The result is: −58xcos(5x+3)+258sin(5x+3)+5cos(5x+3)
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Add the constant of integration:
−58xcos(5x+3)+258sin(5x+3)+5cos(5x+3)+constant
The answer is:
−58xcos(5x+3)+258sin(5x+3)+5cos(5x+3)+constant
The answer (Indefinite)
[src]
/
| cos(3 + 5*x) 8*sin(3 + 5*x) 8*x*cos(3 + 5*x)
| (8*x - 1)*sin(5*x + 3) dx = C + ------------ + -------------- - ----------------
| 5 25 5
/
∫(8x−1)sin(5x+3)dx=C−58xcos(5x+3)+258sin(5x+3)+5cos(5x+3)
The graph
8*sin(3) 7*cos(8) cos(3) 8*sin(8)
- -------- - -------- - ------ + --------
25 5 5 25
−258sin(3)−5cos(3)−57cos(8)+258sin(8)
=
8*sin(3) 7*cos(8) cos(3) 8*sin(8)
- -------- - -------- - ------ + --------
25 5 5 25
−258sin(3)−5cos(3)−57cos(8)+258sin(8)
-8*sin(3)/25 - 7*cos(8)/5 - cos(3)/5 + 8*sin(8)/25
Use the examples entering the upper and lower limits of integration.