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(x^3-1)/(x+3)

Integral of (x^3-1)/(x+3) dx

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The solution

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  1          
  /          
 |           
 |   3       
 |  x  - 1   
 |  ------ dx
 |  x + 3    
 |           
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0            
01x31x+3dx\int\limits_{0}^{1} \frac{x^{3} - 1}{x + 3}\, dx
Integral((x^3 - 1*1)/(x + 3), (x, 0, 1))
Detail solution
  1. There are multiple ways to do this integral.

    Method #1

    1. Rewrite the integrand:

      x31x+3=x23x+928x+3\frac{x^{3} - 1}{x + 3} = x^{2} - 3 x + 9 - \frac{28}{x + 3}

    2. Integrate term-by-term:

      1. The integral of xnx^{n} is xn+1n+1\frac{x^{n + 1}}{n + 1} when n1n \neq -1:

        x2dx=x33\int x^{2}\, dx = \frac{x^{3}}{3}

      1. The integral of a constant times a function is the constant times the integral of the function:

        (3x)dx=3xdx\int \left(- 3 x\right)\, dx = - 3 \int x\, dx

        1. The integral of xnx^{n} is xn+1n+1\frac{x^{n + 1}}{n + 1} when n1n \neq -1:

          xdx=x22\int x\, dx = \frac{x^{2}}{2}

        So, the result is: 3x22- \frac{3 x^{2}}{2}

      1. The integral of a constant is the constant times the variable of integration:

        9dx=9x\int 9\, dx = 9 x

      1. The integral of a constant times a function is the constant times the integral of the function:

        (28x+3)dx=281x+3dx\int \left(- \frac{28}{x + 3}\right)\, dx = - 28 \int \frac{1}{x + 3}\, dx

        1. Let u=x+3u = x + 3.

          Then let du=dxdu = dx and substitute dudu:

          1udu\int \frac{1}{u}\, du

          1. The integral of 1u\frac{1}{u} is log(u)\log{\left(u \right)}.

          Now substitute uu back in:

          log(x+3)\log{\left(x + 3 \right)}

        So, the result is: 28log(x+3)- 28 \log{\left(x + 3 \right)}

      The result is: x333x22+9x28log(x+3)\frac{x^{3}}{3} - \frac{3 x^{2}}{2} + 9 x - 28 \log{\left(x + 3 \right)}

    Method #2

    1. Rewrite the integrand:

      x31x+3=x3x+31x+3\frac{x^{3} - 1}{x + 3} = \frac{x^{3}}{x + 3} - \frac{1}{x + 3}

    2. Integrate term-by-term:

      1. Rewrite the integrand:

        x3x+3=x23x+927x+3\frac{x^{3}}{x + 3} = x^{2} - 3 x + 9 - \frac{27}{x + 3}

      2. Integrate term-by-term:

        1. The integral of xnx^{n} is xn+1n+1\frac{x^{n + 1}}{n + 1} when n1n \neq -1:

          x2dx=x33\int x^{2}\, dx = \frac{x^{3}}{3}

        1. The integral of a constant times a function is the constant times the integral of the function:

          (3x)dx=3xdx\int \left(- 3 x\right)\, dx = - 3 \int x\, dx

          1. The integral of xnx^{n} is xn+1n+1\frac{x^{n + 1}}{n + 1} when n1n \neq -1:

            xdx=x22\int x\, dx = \frac{x^{2}}{2}

          So, the result is: 3x22- \frac{3 x^{2}}{2}

        1. The integral of a constant is the constant times the variable of integration:

          9dx=9x\int 9\, dx = 9 x

        1. The integral of a constant times a function is the constant times the integral of the function:

          (27x+3)dx=271x+3dx\int \left(- \frac{27}{x + 3}\right)\, dx = - 27 \int \frac{1}{x + 3}\, dx

          1. Let u=x+3u = x + 3.

            Then let du=dxdu = dx and substitute dudu:

            1udu\int \frac{1}{u}\, du

            1. The integral of 1u\frac{1}{u} is log(u)\log{\left(u \right)}.

            Now substitute uu back in:

            log(x+3)\log{\left(x + 3 \right)}

          So, the result is: 27log(x+3)- 27 \log{\left(x + 3 \right)}

        The result is: x333x22+9x27log(x+3)\frac{x^{3}}{3} - \frac{3 x^{2}}{2} + 9 x - 27 \log{\left(x + 3 \right)}

      1. The integral of a constant times a function is the constant times the integral of the function:

        (1x+3)dx=1x+3dx\int \left(- \frac{1}{x + 3}\right)\, dx = - \int \frac{1}{x + 3}\, dx

        1. Let u=x+3u = x + 3.

          Then let du=dxdu = dx and substitute dudu:

          1udu\int \frac{1}{u}\, du

          1. The integral of 1u\frac{1}{u} is log(u)\log{\left(u \right)}.

          Now substitute uu back in:

          log(x+3)\log{\left(x + 3 \right)}

        So, the result is: log(x+3)- \log{\left(x + 3 \right)}

      The result is: x333x22+9x27log(x+3)log(x+3)\frac{x^{3}}{3} - \frac{3 x^{2}}{2} + 9 x - 27 \log{\left(x + 3 \right)} - \log{\left(x + 3 \right)}

  2. Add the constant of integration:

    x333x22+9x28log(x+3)+constant\frac{x^{3}}{3} - \frac{3 x^{2}}{2} + 9 x - 28 \log{\left(x + 3 \right)}+ \mathrm{constant}


The answer is:

x333x22+9x28log(x+3)+constant\frac{x^{3}}{3} - \frac{3 x^{2}}{2} + 9 x - 28 \log{\left(x + 3 \right)}+ \mathrm{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 
 |                                                
/                                                 
x31x+3dx=C+x333x22+9x28log(x+3)\int \frac{x^{3} - 1}{x + 3}\, dx = C + \frac{x^{3}}{3} - \frac{3 x^{2}}{2} + 9 x - 28 \log{\left(x + 3 \right)}
The graph
0.001.000.100.200.300.400.500.600.700.800.90-5050
The answer [src]
47/6 - 28*log(4) + 28*log(3)
28log(4)+476+28log(3)- 28 \log{\left(4 \right)} + \frac{47}{6} + 28 \log{\left(3 \right)}
=
=
47/6 - 28*log(4) + 28*log(3)
28log(4)+476+28log(3)- 28 \log{\left(4 \right)} + \frac{47}{6} + 28 \log{\left(3 \right)}
Numerical answer [src]
-0.221764695316533
-0.221764695316533
The graph
Integral of (x^3-1)/(x+3) dx

    Use the examples entering the upper and lower limits of integration.