Sr Examen

Derivada de (xsinx)/(x+tgx)

Función f() - derivada -er orden en el punto
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Gráfico:

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Definida a trozos:

Solución

Ha introducido [src]
 x*sin(x) 
----------
x + tan(x)
xsin(x)x+tan(x)\frac{x \sin{\left(x \right)}}{x + \tan{\left(x \right)}}
(x*sin(x))/(x + tan(x))
Solución detallada
  1. Se aplica la regla de la derivada parcial:

    ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)g2(x)\frac{d}{d x} \frac{f{\left(x \right)}}{g{\left(x \right)}} = \frac{- f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}}{g^{2}{\left(x \right)}}

    f(x)=xsin(x)f{\left(x \right)} = x \sin{\left(x \right)} y g(x)=x+tan(x)g{\left(x \right)} = x + \tan{\left(x \right)}.

    Para calcular ddxf(x)\frac{d}{d x} f{\left(x \right)}:

    1. Se aplica la regla de la derivada de una multiplicación:

      ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)\frac{d}{d x} f{\left(x \right)} g{\left(x \right)} = f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}

      f(x)=xf{\left(x \right)} = x; calculamos ddxf(x)\frac{d}{d x} f{\left(x \right)}:

      1. Según el principio, aplicamos: xx tenemos 11

      g(x)=sin(x)g{\left(x \right)} = \sin{\left(x \right)}; calculamos ddxg(x)\frac{d}{d x} g{\left(x \right)}:

      1. La derivada del seno es igual al coseno:

        ddxsin(x)=cos(x)\frac{d}{d x} \sin{\left(x \right)} = \cos{\left(x \right)}

      Como resultado de: xcos(x)+sin(x)x \cos{\left(x \right)} + \sin{\left(x \right)}

    Para calcular ddxg(x)\frac{d}{d x} g{\left(x \right)}:

    1. diferenciamos x+tan(x)x + \tan{\left(x \right)} miembro por miembro:

      1. Según el principio, aplicamos: xx tenemos 11

      2. Reescribimos las funciones para diferenciar:

        tan(x)=sin(x)cos(x)\tan{\left(x \right)} = \frac{\sin{\left(x \right)}}{\cos{\left(x \right)}}

      3. Se aplica la regla de la derivada parcial:

        ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)g2(x)\frac{d}{d x} \frac{f{\left(x \right)}}{g{\left(x \right)}} = \frac{- f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}}{g^{2}{\left(x \right)}}

        f(x)=sin(x)f{\left(x \right)} = \sin{\left(x \right)} y g(x)=cos(x)g{\left(x \right)} = \cos{\left(x \right)}.

        Para calcular ddxf(x)\frac{d}{d x} f{\left(x \right)}:

        1. La derivada del seno es igual al coseno:

          ddxsin(x)=cos(x)\frac{d}{d x} \sin{\left(x \right)} = \cos{\left(x \right)}

        Para calcular ddxg(x)\frac{d}{d x} g{\left(x \right)}:

        1. La derivada del coseno es igual a menos el seno:

          ddxcos(x)=sin(x)\frac{d}{d x} \cos{\left(x \right)} = - \sin{\left(x \right)}

        Ahora aplicamos la regla de la derivada de una divesión:

        sin2(x)+cos2(x)cos2(x)\frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}}

      Como resultado de: sin2(x)+cos2(x)cos2(x)+1\frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1

    Ahora aplicamos la regla de la derivada de una divesión:

    x(sin2(x)+cos2(x)cos2(x)+1)sin(x)+(x+tan(x))(xcos(x)+sin(x))(x+tan(x))2\frac{- x \left(\frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1\right) \sin{\left(x \right)} + \left(x + \tan{\left(x \right)}\right) \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right)}{\left(x + \tan{\left(x \right)}\right)^{2}}

  2. Simplificamos:

    x2cos(x)xsin3(x)cos2(x)+sin2(x)cos(x)(x+tan(x))2\frac{x^{2} \cos{\left(x \right)} - \frac{x \sin^{3}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{\sin^{2}{\left(x \right)}}{\cos{\left(x \right)}}}{\left(x + \tan{\left(x \right)}\right)^{2}}


Respuesta:

x2cos(x)xsin3(x)cos2(x)+sin2(x)cos(x)(x+tan(x))2\frac{x^{2} \cos{\left(x \right)} - \frac{x \sin^{3}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{\sin^{2}{\left(x \right)}}{\cos{\left(x \right)}}}{\left(x + \tan{\left(x \right)}\right)^{2}}

Gráfica
02468-8-6-4-2-1010-100000100000
Primera derivada [src]
                      /        2   \       
x*cos(x) + sin(x)   x*\-2 - tan (x)/*sin(x)
----------------- + -----------------------
    x + tan(x)                       2     
                         (x + tan(x))      
x(tan2(x)2)sin(x)(x+tan(x))2+xcos(x)+sin(x)x+tan(x)\frac{x \left(- \tan^{2}{\left(x \right)} - 2\right) \sin{\left(x \right)}}{\left(x + \tan{\left(x \right)}\right)^{2}} + \frac{x \cos{\left(x \right)} + \sin{\left(x \right)}}{x + \tan{\left(x \right)}}
Segunda derivada [src]
 /                                                                 /                                    2\       \ 
 |                                                                 |                       /       2   \ |       | 
 |                                                                 |/       2   \          \2 + tan (x)/ |       | 
 |                         /       2   \                       2*x*|\1 + tan (x)/*tan(x) - --------------|*sin(x)| 
 |                       2*\2 + tan (x)/*(x*cos(x) + sin(x))       \                         x + tan(x)  /       | 
-|-2*cos(x) + x*sin(x) + ----------------------------------- + --------------------------------------------------| 
 \                                    x + tan(x)                                   x + tan(x)                    / 
-------------------------------------------------------------------------------------------------------------------
                                                     x + tan(x)                                                    
xsin(x)+2x((tan2(x)+1)tan(x)(tan2(x)+2)2x+tan(x))sin(x)x+tan(x)2cos(x)+2(xcos(x)+sin(x))(tan2(x)+2)x+tan(x)x+tan(x)- \frac{x \sin{\left(x \right)} + \frac{2 x \left(\left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)} - \frac{\left(\tan^{2}{\left(x \right)} + 2\right)^{2}}{x + \tan{\left(x \right)}}\right) \sin{\left(x \right)}}{x + \tan{\left(x \right)}} - 2 \cos{\left(x \right)} + \frac{2 \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 2\right)}{x + \tan{\left(x \right)}}}{x + \tan{\left(x \right)}}
Tercera derivada [src]
                                                                                                                                    /                                                          3                                       \       
                                             /                                    2\                                                |             2                               /       2   \      /       2   \ /       2   \       |       
                                             |                       /       2   \ |                                                |/       2   \         2    /       2   \   3*\2 + tan (x)/    6*\1 + tan (x)/*\2 + tan (x)/*tan(x)|       
                                             |/       2   \          \2 + tan (x)/ |                                            2*x*|\1 + tan (x)/  + 2*tan (x)*\1 + tan (x)/ + ---------------- - ------------------------------------|*sin(x)
                       6*(x*cos(x) + sin(x))*|\1 + tan (x)/*tan(x) - --------------|     /       2   \                              |                                                        2                  x + tan(x)             |       
                                             \                         x + tan(x)  /   3*\2 + tan (x)/*(-2*cos(x) + x*sin(x))       \                                            (x + tan(x))                                          /       
-3*sin(x) - x*cos(x) - ------------------------------------------------------------- + -------------------------------------- - ---------------------------------------------------------------------------------------------------------------
                                                 x + tan(x)                                          x + tan(x)                                                                    x + tan(x)                                                  
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                   x + tan(x)                                                                                                                  
xcos(x)2x((tan2(x)+1)2+2(tan2(x)+1)tan2(x)6(tan2(x)+1)(tan2(x)+2)tan(x)x+tan(x)+3(tan2(x)+2)3(x+tan(x))2)sin(x)x+tan(x)3sin(x)+3(xsin(x)2cos(x))(tan2(x)+2)x+tan(x)6(xcos(x)+sin(x))((tan2(x)+1)tan(x)(tan2(x)+2)2x+tan(x))x+tan(x)x+tan(x)\frac{- x \cos{\left(x \right)} - \frac{2 x \left(\left(\tan^{2}{\left(x \right)} + 1\right)^{2} + 2 \left(\tan^{2}{\left(x \right)} + 1\right) \tan^{2}{\left(x \right)} - \frac{6 \left(\tan^{2}{\left(x \right)} + 1\right) \left(\tan^{2}{\left(x \right)} + 2\right) \tan{\left(x \right)}}{x + \tan{\left(x \right)}} + \frac{3 \left(\tan^{2}{\left(x \right)} + 2\right)^{3}}{\left(x + \tan{\left(x \right)}\right)^{2}}\right) \sin{\left(x \right)}}{x + \tan{\left(x \right)}} - 3 \sin{\left(x \right)} + \frac{3 \left(x \sin{\left(x \right)} - 2 \cos{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 2\right)}{x + \tan{\left(x \right)}} - \frac{6 \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \left(\left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)} - \frac{\left(\tan^{2}{\left(x \right)} + 2\right)^{2}}{x + \tan{\left(x \right)}}\right)}{x + \tan{\left(x \right)}}}{x + \tan{\left(x \right)}}
Gráfico
Derivada de (xsinx)/(x+tgx)