Integral of arcsin2x dx
The solution
Detail solution
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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 2du:
∫2asin(u)du
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The integral of a constant times a function is the constant times the integral of the function:
∫asin(u)du=2∫asin(u)du
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Use integration by parts:
∫udv=uv−∫vdu
Let u(u)=asin(u) and let dv(u)=1.
Then du(u)=1−u21.
To find v(u):
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The integral of a constant is the constant times the variable of integration:
∫1du=u
Now evaluate the sub-integral.
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Let u=1−u2.
Then let du=−2udu and substitute −2du:
∫(−2u1)du
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The integral of a constant times a function is the constant times the integral of the function:
∫u1du=−2∫u1du
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The integral of un is n+1un+1 when n=−1:
∫u1du=2u
So, the result is: −u
Now substitute u back in:
−1−u2
So, the result is: 2uasin(u)+21−u2
Now substitute u back in:
xasin(2x)+21−4x2
Method #2
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Use integration by parts:
∫udv=uv−∫vdu
Let u(x)=asin(2x) and let dv(x)=1.
Then du(x)=1−4x22.
To find v(x):
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The integral of a constant is the constant times the variable of integration:
∫1dx=x
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:
∫1−4x22xdx=2∫1−4x2xdx
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Let u=1−4x2.
Then let du=−8xdx and substitute −8du:
∫(−8u1)du
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The integral of a constant times a function is the constant times the integral of the function:
∫u1du=−8∫u1du
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The integral of un is n+1un+1 when n=−1:
∫u1du=2u
So, the result is: −4u
Now substitute u back in:
−41−4x2
So, the result is: −21−4x2
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Add the constant of integration:
xasin(2x)+21−4x2+constant
The answer is:
xasin(2x)+21−4x2+constant
The answer (Indefinite)
[src]
__________
/ / 2
| \/ 1 - 4*x
| asin(2*x) dx = C + ------------- + x*asin(2*x)
| 2
/
∫asin(2x)dx=C+xasin(2x)+21−4x2
The graph
___
1 \/ 3 pi
- - + ----- + --
2 4 24
−21+24π+43
=
___
1 \/ 3 pi
- - + ----- + --
2 4 24
−21+24π+43
Use the examples entering the upper and lower limits of integration.