Integral of (x^3-1)/(x+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:
x+3x3−1=x2−3x+9−x+328
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Integrate term-by-term:
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The integral of xn is n+1xn+1 when n=−1:
∫x2dx=3x3
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The integral of a constant times a function is the constant times the integral of the function:
∫(−3x)dx=−3∫xdx
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The integral of xn is n+1xn+1 when n=−1:
∫xdx=2x2
So, the result is: −23x2
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The integral of a constant is the constant times the variable of integration:
∫9dx=9x
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The integral of a constant times a function is the constant times the integral of the function:
∫(−x+328)dx=−28∫x+31dx
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Let u=x+3.
Then let du=dx and substitute du:
∫u1du
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The integral of u1 is log(u).
Now substitute u back in:
log(x+3)
So, the result is: −28log(x+3)
The result is: 3x3−23x2+9x−28log(x+3)
Method #2
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Rewrite the integrand:
x+3x3−1=x+3x3−x+31
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Integrate term-by-term:
-
Rewrite the integrand:
x+3x3=x2−3x+9−x+327
-
Integrate term-by-term:
-
The integral of xn is n+1xn+1 when n=−1:
∫x2dx=3x3
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−3x)dx=−3∫xdx
-
The integral of xn is n+1xn+1 when n=−1:
∫xdx=2x2
So, the result is: −23x2
-
The integral of a constant is the constant times the variable of integration:
∫9dx=9x
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−x+327)dx=−27∫x+31dx
-
Let u=x+3.
Then let du=dx and substitute du:
∫u1du
-
The integral of u1 is log(u).
Now substitute u back in:
log(x+3)
So, the result is: −27log(x+3)
The result is: 3x3−23x2+9x−27log(x+3)
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−x+31)dx=−∫x+31dx
-
Let u=x+3.
Then let du=dx and substitute du:
∫u1du
-
The integral of u1 is log(u).
Now substitute u back in:
log(x+3)
So, the result is: −log(x+3)
The result is: 3x3−23x2+9x−27log(x+3)−log(x+3)
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Add the constant of integration:
3x3−23x2+9x−28log(x+3)+constant
The answer is:
3x3−23x2+9x−28log(x+3)+constant
The answer (Indefinite)
[src]
/
|
| 3 2 3
| x - 1 3*x x
| ------ dx = C - 28*log(3 + x) + 9*x - ---- + --
| x + 3 2 3
|
/
∫x+3x3−1dx=C+3x3−23x2+9x−28log(x+3)
The graph
47/6 - 28*log(4) + 28*log(3)
−28log(4)+647+28log(3)
=
47/6 - 28*log(4) + 28*log(3)
−28log(4)+647+28log(3)
Use the examples entering the upper and lower limits of integration.