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Integral de 1/2*ln(|x+1|) dx

Límites de integración:

interior superior
v

Gráfico:

interior superior

Definida a trozos:

Solución

Ha introducido [src]
  1                
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 |  log(|x + 1|)   
 |  ------------ dx
 |       2         
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0                  
01log(x+1)2dx\int\limits_{0}^{1} \frac{\log{\left(\left|{x + 1}\right| \right)}}{2}\, dx
Integral(log(|x + 1|)/2, (x, 0, 1))
Solución detallada
  1. La integral del producto de una función por una constante es la constante por la integral de esta función:

    log(x+1)2dx=log(x+1)dx2\int \frac{\log{\left(\left|{x + 1}\right| \right)}}{2}\, dx = \frac{\int \log{\left(\left|{x + 1}\right| \right)}\, dx}{2}

    1. Usamos la integración por partes:

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

      que u(x)=log(x+1)u{\left(x \right)} = \log{\left(\left|{x + 1}\right| \right)} y que dv(x)=1\operatorname{dv}{\left(x \right)} = 1.

      Entonces du(x)=((re(x)+1)ddxre(x)+im(x)ddxim(x))sign(x+1)(x+1)x+1\operatorname{du}{\left(x \right)} = \frac{\left(\left(\operatorname{re}{\left(x\right)} + 1\right) \frac{d}{d x} \operatorname{re}{\left(x\right)} + \operatorname{im}{\left(x\right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}\right) \operatorname{sign}{\left(x + 1 \right)}}{\left(x + 1\right) \left|{x + 1}\right|}.

      Para buscar v(x)v{\left(x \right)}:

      1. La integral de las constantes tienen esta constante multiplicada por la variable de integración:

        1dx=x\int 1\, dx = x

      Ahora resolvemos podintegral.

    2. Hay varias maneras de calcular esta integral.

      Método #1

      1. Vuelva a escribir el integrando:

        x((re(x)+1)ddxre(x)+im(x)ddxim(x))sign(x+1)(x+1)x+1=xre(x)sign(x+1)ddxre(x)+xim(x)sign(x+1)ddxim(x)+xsign(x+1)ddxre(x)xx+1+x+1\frac{x \left(\left(\operatorname{re}{\left(x\right)} + 1\right) \frac{d}{d x} \operatorname{re}{\left(x\right)} + \operatorname{im}{\left(x\right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}\right) \operatorname{sign}{\left(x + 1 \right)}}{\left(x + 1\right) \left|{x + 1}\right|} = \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)} + x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)} + x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|}

      2. Vuelva a escribir el integrando:

        xre(x)sign(x+1)ddxre(x)+xim(x)sign(x+1)ddxim(x)+xsign(x+1)ddxre(x)xx+1+x+1=xre(x)sign(x+1)ddxre(x)xx+1+x+1+xim(x)sign(x+1)ddxim(x)xx+1+x+1+xsign(x+1)ddxre(x)xx+1+x+1\frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)} + x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)} + x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|} = \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|} + \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|} + \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|}

      3. Integramos término a término:

        1. No puedo encontrar los pasos en la búsqueda de esta integral.

          Pero la integral

          xre(x)sign(x+1)ddxre(x)(x+1)x+1dx\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

        1. No puedo encontrar los pasos en la búsqueda de esta integral.

          Pero la integral

          xim(x)sign(x+1)ddxim(x)(x+1)x+1dx\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

        1. No puedo encontrar los pasos en la búsqueda de esta integral.

          Pero la integral

          xsign(x+1)ddxre(x)(x+1)x+1dx\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

        El resultado es: xsign(x+1)ddxre(x)(x+1)x+1dx+xre(x)sign(x+1)ddxre(x)(x+1)x+1dx+xim(x)sign(x+1)ddxim(x)(x+1)x+1dx\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx + \int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx + \int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

      Método #2

      1. Vuelva a escribir el integrando:

        x((re(x)+1)ddxre(x)+im(x)ddxim(x))sign(x+1)(x+1)x+1=xre(x)sign(x+1)ddxre(x)xx+1+x+1+xim(x)sign(x+1)ddxim(x)xx+1+x+1+xsign(x+1)ddxre(x)xx+1+x+1\frac{x \left(\left(\operatorname{re}{\left(x\right)} + 1\right) \frac{d}{d x} \operatorname{re}{\left(x\right)} + \operatorname{im}{\left(x\right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}\right) \operatorname{sign}{\left(x + 1 \right)}}{\left(x + 1\right) \left|{x + 1}\right|} = \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|} + \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|} + \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{x \left|{x + 1}\right| + \left|{x + 1}\right|}

      2. Integramos término a término:

        1. No puedo encontrar los pasos en la búsqueda de esta integral.

          Pero la integral

          xre(x)sign(x+1)ddxre(x)(x+1)x+1dx\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

        1. No puedo encontrar los pasos en la búsqueda de esta integral.

          Pero la integral

          xim(x)sign(x+1)ddxim(x)(x+1)x+1dx\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

        1. No puedo encontrar los pasos en la búsqueda de esta integral.

          Pero la integral

          xsign(x+1)ddxre(x)(x+1)x+1dx\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

        El resultado es: xsign(x+1)ddxre(x)(x+1)x+1dx+xre(x)sign(x+1)ddxre(x)(x+1)x+1dx+xim(x)sign(x+1)ddxim(x)(x+1)x+1dx\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx + \int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx + \int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx

    Por lo tanto, el resultado es: xlog(x+1)2xsign(x+1)ddxre(x)(x+1)x+1dx2xre(x)sign(x+1)ddxre(x)(x+1)x+1dx2xim(x)sign(x+1)ddxim(x)(x+1)x+1dx2\frac{x \log{\left(\left|{x + 1}\right| \right)}}{2} - \frac{\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2}

  2. Ahora simplificar:

    xlog(x+1)2xsign(x+1)ddxre(x)(x+1)x+1dx2xre(x)sign(x+1)ddxre(x)(x+1)x+1dx2xim(x)sign(x+1)ddxim(x)(x+1)x+1dx2\frac{x \log{\left(\left|{x + 1}\right| \right)}}{2} - \frac{\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2}

  3. Añadimos la constante de integración:

    xlog(x+1)2xsign(x+1)ddxre(x)(x+1)x+1dx2xre(x)sign(x+1)ddxre(x)(x+1)x+1dx2xim(x)sign(x+1)ddxim(x)(x+1)x+1dx2+constant\frac{x \log{\left(\left|{x + 1}\right| \right)}}{2} - \frac{\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2}+ \mathrm{constant}


Respuesta:

xlog(x+1)2xsign(x+1)ddxre(x)(x+1)x+1dx2xre(x)sign(x+1)ddxre(x)(x+1)x+1dx2xim(x)sign(x+1)ddxim(x)(x+1)x+1dx2+constant\frac{x \log{\left(\left|{x + 1}\right| \right)}}{2} - \frac{\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2}+ \mathrm{constant}

Respuesta (Indefinida) [src]
                           /                               /                                     /                                                 
                          |                               |                                     |                                                  
                          |   d                           |   d                                 |   d                                              
                          | x*--(re(x))*sign(1 + x)       | x*--(im(x))*im(x)*sign(1 + x)       | x*--(re(x))*re(x)*sign(1 + x)                    
                          |   dx                          |   dx                                |   dx                                             
                          | ----------------------- dx    | ----------------------------- dx    | ----------------------------- dx                 
  /                       |     (1 + x)*|1 + x|           |        (1 + x)*|1 + x|              |        (1 + x)*|1 + x|                           
 |                        |                               |                                     |                                                  
 | log(|x + 1|)          /                               /                                     /                                     x*log(|x + 1|)
 | ------------ dx = C - ----------------------------- - ----------------------------------- - ----------------------------------- + --------------
 |      2                              2                                  2                                     2                          2       
 |                                                                                                                                                 
/                                                                                                                                                  
log(x+1)2dx=C+xlog(x+1)2xsign(x+1)ddxre(x)(x+1)x+1dx2xre(x)sign(x+1)ddxre(x)(x+1)x+1dx2xim(x)sign(x+1)ddxim(x)(x+1)x+1dx2\int \frac{\log{\left(\left|{x + 1}\right| \right)}}{2}\, dx = C + \frac{x \log{\left(\left|{x + 1}\right| \right)}}{2} - \frac{\int \frac{x \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{re}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{re}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2} - \frac{\int \frac{x \operatorname{im}{\left(x\right)} \operatorname{sign}{\left(x + 1 \right)} \frac{d}{d x} \operatorname{im}{\left(x\right)}}{\left(x + 1\right) \left|{x + 1}\right|}\, dx}{2}
Gráfica
0.001.000.100.200.300.400.500.600.700.800.900.00.5
Respuesta [src]
-1/2 + log(2)
12+log(2)- \frac{1}{2} + \log{\left(2 \right)}
=
=
-1/2 + log(2)
12+log(2)- \frac{1}{2} + \log{\left(2 \right)}
-1/2 + log(2)
Respuesta numérica [src]
0.193147180559945
0.193147180559945

    Estos ejemplos se pueden aplicar para introducción de los límites de integración inferior y superior.