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Integral of (1-log(x))/x dx

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1ex1log(x)xdx\int\limits_{1}^{e^{x}} \frac{1 - \log{\left(x \right)}}{x}\, dx
Integral((1 - log(x))/x, (x, 1, exp(x)))
Detail solution
  1. There are multiple ways to do this integral.

    Method #1

    1. Let u=1log(x)u = 1 - \log{\left(x \right)}.

      Then let du=dxxdu = - \frac{dx}{x} and substitute du- du:

      (u)du\int \left(- u\right)\, du

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

        udu=udu\int u\, du = - \int u\, du

        1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

          udu=u22\int u\, du = \frac{u^{2}}{2}

        So, the result is: u22- \frac{u^{2}}{2}

      Now substitute uu back in:

      (1log(x))22- \frac{\left(1 - \log{\left(x \right)}\right)^{2}}{2}

    Method #2

    1. Rewrite the integrand:

      1log(x)x=log(x)1x\frac{1 - \log{\left(x \right)}}{x} = - \frac{\log{\left(x \right)} - 1}{x}

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

      (log(x)1x)dx=log(x)1xdx\int \left(- \frac{\log{\left(x \right)} - 1}{x}\right)\, dx = - \int \frac{\log{\left(x \right)} - 1}{x}\, dx

      1. Let u=1xu = \frac{1}{x}.

        Then let du=dxx2du = - \frac{dx}{x^{2}} and substitute du- du:

        (log(1u)1u)du\int \left(- \frac{\log{\left(\frac{1}{u} \right)} - 1}{u}\right)\, du

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

          log(1u)1udu=log(1u)1udu\int \frac{\log{\left(\frac{1}{u} \right)} - 1}{u}\, du = - \int \frac{\log{\left(\frac{1}{u} \right)} - 1}{u}\, du

          1. Let u=log(1u)1u = \log{\left(\frac{1}{u} \right)} - 1.

            Then let du=duudu = - \frac{du}{u} and substitute du- du:

            (u)du\int \left(- u\right)\, du

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

              udu=udu\int u\, du = - \int u\, du

              1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

                udu=u22\int u\, du = \frac{u^{2}}{2}

              So, the result is: u22- \frac{u^{2}}{2}

            Now substitute uu back in:

            (log(1u)1)22- \frac{\left(\log{\left(\frac{1}{u} \right)} - 1\right)^{2}}{2}

          So, the result is: (log(1u)1)22\frac{\left(\log{\left(\frac{1}{u} \right)} - 1\right)^{2}}{2}

        Now substitute uu back in:

        (log(x)1)22\frac{\left(\log{\left(x \right)} - 1\right)^{2}}{2}

      So, the result is: (log(x)1)22- \frac{\left(\log{\left(x \right)} - 1\right)^{2}}{2}

    Method #3

    1. Rewrite the integrand:

      1log(x)x=log(x)x+1x\frac{1 - \log{\left(x \right)}}{x} = - \frac{\log{\left(x \right)}}{x} + \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:

        (log(x)x)dx=log(x)xdx\int \left(- \frac{\log{\left(x \right)}}{x}\right)\, dx = - \int \frac{\log{\left(x \right)}}{x}\, dx

        1. Let u=1xu = \frac{1}{x}.

          Then let du=dxx2du = - \frac{dx}{x^{2}} and substitute du- du:

          (log(1u)u)du\int \left(- \frac{\log{\left(\frac{1}{u} \right)}}{u}\right)\, du

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

            log(1u)udu=log(1u)udu\int \frac{\log{\left(\frac{1}{u} \right)}}{u}\, du = - \int \frac{\log{\left(\frac{1}{u} \right)}}{u}\, du

            1. Let u=log(1u)u = \log{\left(\frac{1}{u} \right)}.

              Then let du=duudu = - \frac{du}{u} and substitute du- du:

              (u)du\int \left(- u\right)\, du

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

                udu=udu\int u\, du = - \int u\, du

                1. The integral of unu^{n} is un+1n+1\frac{u^{n + 1}}{n + 1} when n1n \neq -1:

                  udu=u22\int u\, du = \frac{u^{2}}{2}

                So, the result is: u22- \frac{u^{2}}{2}

              Now substitute uu back in:

              log(1u)22- \frac{\log{\left(\frac{1}{u} \right)}^{2}}{2}

            So, the result is: log(1u)22\frac{\log{\left(\frac{1}{u} \right)}^{2}}{2}

          Now substitute uu back in:

          log(x)22\frac{\log{\left(x \right)}^{2}}{2}

        So, the result is: log(x)22- \frac{\log{\left(x \right)}^{2}}{2}

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

      The result is: log(x)22+log(x)- \frac{\log{\left(x \right)}^{2}}{2} + \log{\left(x \right)}

  2. Now simplify:

    (log(x)1)22- \frac{\left(\log{\left(x \right)} - 1\right)^{2}}{2}

  3. Add the constant of integration:

    (log(x)1)22+constant- \frac{\left(\log{\left(x \right)} - 1\right)^{2}}{2}+ \mathrm{constant}


The answer is:

(log(x)1)22+constant- \frac{\left(\log{\left(x \right)} - 1\right)^{2}}{2}+ \mathrm{constant}

The answer (Indefinite) [src]
  /                                 
 |                                 2
 | 1 - log(x)          (1 - log(x)) 
 | ---------- dx = C - -------------
 |     x                     2      
 |                                  
/                                   
1log(x)xdx=C(1log(x))22\int \frac{1 - \log{\left(x \right)}}{x}\, dx = C - \frac{\left(1 - \log{\left(x \right)}\right)^{2}}{2}
The answer [src]
     2/ x\          
  log \e /      / x\
- -------- + log\e /
     2              
log(ex)22+log(ex)- \frac{\log{\left(e^{x} \right)}^{2}}{2} + \log{\left(e^{x} \right)}
=
=
     2/ x\          
  log \e /      / x\
- -------- + log\e /
     2              
log(ex)22+log(ex)- \frac{\log{\left(e^{x} \right)}^{2}}{2} + \log{\left(e^{x} \right)}
-log(exp(x))^2/2 + log(exp(x))

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