Sr Examen

Derivada de x*sinx/lnx

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)
--------
 log(x) 
xsin(x)log(x)\frac{x \sin{\left(x \right)}}{\log{\left(x \right)}}
(x*sin(x))/log(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)=log(x)g{\left(x \right)} = \log{\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. Derivado log(x)\log{\left(x \right)} es 1x\frac{1}{x}.

    Ahora aplicamos la regla de la derivada de una divesión:

    (xcos(x)+sin(x))log(x)sin(x)log(x)2\frac{\left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \log{\left(x \right)} - \sin{\left(x \right)}}{\log{\left(x \right)}^{2}}


Respuesta:

(xcos(x)+sin(x))log(x)sin(x)log(x)2\frac{\left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \log{\left(x \right)} - \sin{\left(x \right)}}{\log{\left(x \right)}^{2}}

Primera derivada [src]
x*cos(x) + sin(x)    sin(x)
----------------- - -------
      log(x)           2   
                    log (x)
xcos(x)+sin(x)log(x)sin(x)log(x)2\frac{x \cos{\left(x \right)} + \sin{\left(x \right)}}{\log{\left(x \right)}} - \frac{\sin{\left(x \right)}}{\log{\left(x \right)}^{2}}
Segunda derivada [src]
                                              /      2   \       
                                              |1 + ------|*sin(x)
                      2*(x*cos(x) + sin(x))   \    log(x)/       
2*cos(x) - x*sin(x) - --------------------- + -------------------
                             x*log(x)               x*log(x)     
-----------------------------------------------------------------
                              log(x)                             
xsin(x)+2cos(x)+(1+2log(x))sin(x)xlog(x)2(xcos(x)+sin(x))xlog(x)log(x)\frac{- x \sin{\left(x \right)} + 2 \cos{\left(x \right)} + \frac{\left(1 + \frac{2}{\log{\left(x \right)}}\right) \sin{\left(x \right)}}{x \log{\left(x \right)}} - \frac{2 \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right)}{x \log{\left(x \right)}}}{\log{\left(x \right)}}
Tercera derivada [src]
                                                    /      3         3   \                                            
                                                  2*|1 + ------ + -------|*sin(x)     /      2   \                    
                                                    |    log(x)      2   |          3*|1 + ------|*(x*cos(x) + sin(x))
                       3*(-2*cos(x) + x*sin(x))     \             log (x)/            \    log(x)/                    
-3*sin(x) - x*cos(x) + ------------------------ - ------------------------------- + ----------------------------------
                               x*log(x)                       2                                  2                    
                                                             x *log(x)                          x *log(x)             
----------------------------------------------------------------------------------------------------------------------
                                                        log(x)                                                        
xcos(x)3sin(x)+3(xsin(x)2cos(x))xlog(x)+3(1+2log(x))(xcos(x)+sin(x))x2log(x)2(1+3log(x)+3log(x)2)sin(x)x2log(x)log(x)\frac{- x \cos{\left(x \right)} - 3 \sin{\left(x \right)} + \frac{3 \left(x \sin{\left(x \right)} - 2 \cos{\left(x \right)}\right)}{x \log{\left(x \right)}} + \frac{3 \left(1 + \frac{2}{\log{\left(x \right)}}\right) \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right)}{x^{2} \log{\left(x \right)}} - \frac{2 \left(1 + \frac{3}{\log{\left(x \right)}} + \frac{3}{\log{\left(x \right)}^{2}}\right) \sin{\left(x \right)}}{x^{2} \log{\left(x \right)}}}{\log{\left(x \right)}}
Gráfico
Derivada de x*sinx/lnx