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Integral of 1/(x(1+x^2)) dx

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0111x(x2+1)dx\int\limits_{0}^{1} 1 \cdot \frac{1}{x \left(x^{2} + 1\right)}\, dx
Integral(1/(x*(1 + x^2)), (x, 0, 1))
Detail solution
  1. There are multiple ways to do this integral.

    Method #1

    1. Rewrite the integrand:

      11x(x2+1)=xx2+1+1x1 \cdot \frac{1}{x \left(x^{2} + 1\right)} = - \frac{x}{x^{2} + 1} + \frac{1}{x}

    2. Integrate term-by-term:

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

        (xx2+1)dx=xx2+1dx\int \left(- \frac{x}{x^{2} + 1}\right)\, dx = - \int \frac{x}{x^{2} + 1}\, dx

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

          xx2+1dx=2xx2+1dx2\int \frac{x}{x^{2} + 1}\, dx = \frac{\int \frac{2 x}{x^{2} + 1}\, dx}{2}

          1. Let u=x2+1u = x^{2} + 1.

            Then let du=2xdxdu = 2 x dx and substitute du2\frac{du}{2}:

            12udu\int \frac{1}{2 u}\, du

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

            Now substitute uu back in:

            log(x2+1)\log{\left(x^{2} + 1 \right)}

          So, the result is: log(x2+1)2\frac{\log{\left(x^{2} + 1 \right)}}{2}

        So, the result is: log(x2+1)2- \frac{\log{\left(x^{2} + 1 \right)}}{2}

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

      The result is: log(x)log(x2+1)2\log{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}

    Method #2

    1. Rewrite the integrand:

      11x(x2+1)=1x3+x1 \cdot \frac{1}{x \left(x^{2} + 1\right)} = \frac{1}{x^{3} + x}

    2. Rewrite the integrand:

      1x3+x=xx2+1+1x\frac{1}{x^{3} + x} = - \frac{x}{x^{2} + 1} + \frac{1}{x}

    3. Integrate term-by-term:

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

        (xx2+1)dx=xx2+1dx\int \left(- \frac{x}{x^{2} + 1}\right)\, dx = - \int \frac{x}{x^{2} + 1}\, dx

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

          xx2+1dx=2xx2+1dx2\int \frac{x}{x^{2} + 1}\, dx = \frac{\int \frac{2 x}{x^{2} + 1}\, dx}{2}

          1. Let u=x2+1u = x^{2} + 1.

            Then let du=2xdxdu = 2 x dx and substitute du2\frac{du}{2}:

            12udu\int \frac{1}{2 u}\, du

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

            Now substitute uu back in:

            log(x2+1)\log{\left(x^{2} + 1 \right)}

          So, the result is: log(x2+1)2\frac{\log{\left(x^{2} + 1 \right)}}{2}

        So, the result is: log(x2+1)2- \frac{\log{\left(x^{2} + 1 \right)}}{2}

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

      The result is: log(x)log(x2+1)2\log{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}

    Method #3

    1. Rewrite the integrand:

      11x(x2+1)=1x3+x1 \cdot \frac{1}{x \left(x^{2} + 1\right)} = \frac{1}{x^{3} + x}

    2. Rewrite the integrand:

      1x3+x=xx2+1+1x\frac{1}{x^{3} + x} = - \frac{x}{x^{2} + 1} + \frac{1}{x}

    3. Integrate term-by-term:

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

        (xx2+1)dx=xx2+1dx\int \left(- \frac{x}{x^{2} + 1}\right)\, dx = - \int \frac{x}{x^{2} + 1}\, dx

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

          xx2+1dx=2xx2+1dx2\int \frac{x}{x^{2} + 1}\, dx = \frac{\int \frac{2 x}{x^{2} + 1}\, dx}{2}

          1. Let u=x2+1u = x^{2} + 1.

            Then let du=2xdxdu = 2 x dx and substitute du2\frac{du}{2}:

            12udu\int \frac{1}{2 u}\, du

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

            Now substitute uu back in:

            log(x2+1)\log{\left(x^{2} + 1 \right)}

          So, the result is: log(x2+1)2\frac{\log{\left(x^{2} + 1 \right)}}{2}

        So, the result is: log(x2+1)2- \frac{\log{\left(x^{2} + 1 \right)}}{2}

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

      The result is: log(x)log(x2+1)2\log{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}

  2. Add the constant of integration:

    log(x)log(x2+1)2+constant\log{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}+ \mathrm{constant}


The answer is:

log(x)log(x2+1)2+constant\log{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}+ \mathrm{constant}

The answer (Indefinite) [src]
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logxlog(x2+1)2\log x-{{\log \left(x^2+1\right)}\over{2}}
The answer [src]
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Numerical answer [src]
43.7438725437129
43.7438725437129

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