Mister Exam

Other calculators


log^2(x)/2x

Integral of log^2(x)/2x dx

Limits of integration:

from to
v

The graph:

from to

Piecewise:

The solution

You have entered [src]
  e             
  /             
 |              
 |     2        
 |  log (x)*x   
 |  --------- dx
 |      2       
 |              
/               
1               
1exlog(x)22dx\int\limits_{1}^{e} \frac{x \log{\left(x \right)}^{2}}{2}\, dx
Integral(log(x)^2*x/2, (x, 1, E))
Detail solution
  1. The integral of a constant times a function is the constant times the integral of the function:

    xlog(x)22dx=xlog(x)2dx2\int \frac{x \log{\left(x \right)}^{2}}{2}\, dx = \frac{\int x \log{\left(x \right)}^{2}\, dx}{2}

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

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

      u2e2udu\int u^{2} e^{2 u}\, du

      1. Use integration by parts:

        udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

        Let u(u)=u2u{\left(u \right)} = u^{2} and let dv(u)=e2u\operatorname{dv}{\left(u \right)} = e^{2 u}.

        Then du(u)=2u\operatorname{du}{\left(u \right)} = 2 u.

        To find v(u)v{\left(u \right)}:

        1. There are multiple ways to do this integral.

          Method #1

          1. Let u=2uu = 2 u.

            Then let du=2dudu = 2 du and substitute du2\frac{du}{2}:

            eu4du\int \frac{e^{u}}{4}\, du

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

              eu2du=eudu2\int \frac{e^{u}}{2}\, du = \frac{\int e^{u}\, du}{2}

              1. The integral of the exponential function is itself.

                eudu=eu\int e^{u}\, du = e^{u}

              So, the result is: eu2\frac{e^{u}}{2}

            Now substitute uu back in:

            e2u2\frac{e^{2 u}}{2}

          Method #2

          1. Let u=e2uu = e^{2 u}.

            Then let du=2e2ududu = 2 e^{2 u} du and substitute du2\frac{du}{2}:

            14du\int \frac{1}{4}\, du

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

              12du=1du2\int \frac{1}{2}\, du = \frac{\int 1\, du}{2}

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

                1du=u\int 1\, du = u

              So, the result is: u2\frac{u}{2}

            Now substitute uu back in:

            e2u2\frac{e^{2 u}}{2}

        Now evaluate the sub-integral.

      2. Use integration by parts:

        udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

        Let u(u)=uu{\left(u \right)} = u and let dv(u)=e2u\operatorname{dv}{\left(u \right)} = e^{2 u}.

        Then du(u)=1\operatorname{du}{\left(u \right)} = 1.

        To find v(u)v{\left(u \right)}:

        1. Let u=2uu = 2 u.

          Then let du=2dudu = 2 du and substitute du2\frac{du}{2}:

          eu4du\int \frac{e^{u}}{4}\, du

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

            eu2du=eudu2\int \frac{e^{u}}{2}\, du = \frac{\int e^{u}\, du}{2}

            1. The integral of the exponential function is itself.

              eudu=eu\int e^{u}\, du = e^{u}

            So, the result is: eu2\frac{e^{u}}{2}

          Now substitute uu back in:

          e2u2\frac{e^{2 u}}{2}

        Now evaluate the sub-integral.

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

        e2u2du=e2udu2\int \frac{e^{2 u}}{2}\, du = \frac{\int e^{2 u}\, du}{2}

        1. Let u=2uu = 2 u.

          Then let du=2dudu = 2 du and substitute du2\frac{du}{2}:

          eu4du\int \frac{e^{u}}{4}\, du

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

            eu2du=eudu2\int \frac{e^{u}}{2}\, du = \frac{\int e^{u}\, du}{2}

            1. The integral of the exponential function is itself.

              eudu=eu\int e^{u}\, du = e^{u}

            So, the result is: eu2\frac{e^{u}}{2}

          Now substitute uu back in:

          e2u2\frac{e^{2 u}}{2}

        So, the result is: e2u4\frac{e^{2 u}}{4}

      Now substitute uu back in:

      x2log(x)22x2log(x)2+x24\frac{x^{2} \log{\left(x \right)}^{2}}{2} - \frac{x^{2} \log{\left(x \right)}}{2} + \frac{x^{2}}{4}

    So, the result is: x2log(x)24x2log(x)4+x28\frac{x^{2} \log{\left(x \right)}^{2}}{4} - \frac{x^{2} \log{\left(x \right)}}{4} + \frac{x^{2}}{8}

  2. Now simplify:

    x2(2log(x)22log(x)+1)8\frac{x^{2} \cdot \left(2 \log{\left(x \right)}^{2} - 2 \log{\left(x \right)} + 1\right)}{8}

  3. Add the constant of integration:

    x2(2log(x)22log(x)+1)8+constant\frac{x^{2} \cdot \left(2 \log{\left(x \right)}^{2} - 2 \log{\left(x \right)} + 1\right)}{8}+ \mathrm{constant}


The answer is:

x2(2log(x)22log(x)+1)8+constant\frac{x^{2} \cdot \left(2 \log{\left(x \right)}^{2} - 2 \log{\left(x \right)} + 1\right)}{8}+ \mathrm{constant}

The answer (Indefinite) [src]
  /                                              
 |                                               
 |    2                2    2           2    2   
 | log (x)*x          x    x *log(x)   x *log (x)
 | --------- dx = C + -- - --------- + ----------
 |     2              8        4           4     
 |                                               
/                                                
xlog(x)22dx=C+x2log(x)24x2log(x)4+x28\int \frac{x \log{\left(x \right)}^{2}}{2}\, dx = C + \frac{x^{2} \log{\left(x \right)}^{2}}{4} - \frac{x^{2} \log{\left(x \right)}}{4} + \frac{x^{2}}{8}
The graph
1.01.21.41.61.82.02.22.42.602
The answer [src]
       2
  1   e 
- - + --
  8   8 
18+e28- \frac{1}{8} + \frac{e^{2}}{8}
=
=
       2
  1   e 
- - + --
  8   8 
18+e28- \frac{1}{8} + \frac{e^{2}}{8}
Numerical answer [src]
0.798632012366331
0.798632012366331
The graph
Integral of log^2(x)/2x dx

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