Integral of cos^4(1/2x) dx
The solution
Detail solution
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Rewrite the integrand:
cos4(2x)=(2cos(x)+21)2
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There are multiple ways to do this integral.
Method #1
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Rewrite the integrand:
(2cos(x)+21)2=4cos2(x)+2cos(x)+41
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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:
∫4cos2(x)dx=4∫cos2(x)dx
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Rewrite the integrand:
cos2(x)=2cos(2x)+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(2x)dx=2∫cos(2x)dx
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Let u=2x.
Then let du=2dx 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(2x)
So, the result is: 4sin(2x)
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The integral of a constant is the constant times the variable of integration:
∫21dx=2x
The result is: 2x+4sin(2x)
So, the result is: 8x+16sin(2x)
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The integral of a constant times a function is the constant times the integral of the function:
∫2cos(x)dx=2∫cos(x)dx
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The integral of cosine is sine:
∫cos(x)dx=sin(x)
So, the result is: 2sin(x)
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The integral of a constant is the constant times the variable of integration:
∫41dx=4x
The result is: 83x+2sin(x)+16sin(2x)
Method #2
-
Rewrite the integrand:
(2cos(x)+21)2=4cos2(x)+2cos(x)+41
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫4cos2(x)dx=4∫cos2(x)dx
-
Rewrite the integrand:
cos2(x)=2cos(2x)+21
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫2cos(2x)dx=2∫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: 4sin(2x)
-
The integral of a constant is the constant times the variable of integration:
∫21dx=2x
The result is: 2x+4sin(2x)
So, the result is: 8x+16sin(2x)
-
The integral of a constant times a function is the constant times the integral of the function:
∫2cos(x)dx=2∫cos(x)dx
-
The integral of cosine is sine:
∫cos(x)dx=sin(x)
So, the result is: 2sin(x)
-
The integral of a constant is the constant times the variable of integration:
∫41dx=4x
The result is: 83x+2sin(x)+16sin(2x)
-
Add the constant of integration:
83x+2sin(x)+16sin(2x)+constant
The answer is:
83x+2sin(x)+16sin(2x)+constant
The answer (Indefinite)
[src]
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|
| 4/x\ sin(x) sin(2*x) 3*x
| cos |-| dx = C + ------ + -------- + ---
| \2/ 2 16 8
|
/
82sin(2x)+x+2sinx+4x
The graph
3
3 cos (1/2)*sin(1/2) 3*cos(1/2)*sin(1/2)
- + ------------------ + -------------------
8 2 4
16sin2+8sin1+6
=
3
3 cos (1/2)*sin(1/2) 3*cos(1/2)*sin(1/2)
- + ------------------ + -------------------
8 2 4
2sin(21)cos3(21)+43sin(21)cos(21)+83
Use the examples entering the upper and lower limits of integration.