Sr Examen

Derivada de x*lnx/cosx

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*log(x)
--------
 cos(x) 
xlog(x)cos(x)\frac{x \log{\left(x \right)}}{\cos{\left(x \right)}}
(x*log(x))/cos(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)=xlog(x)f{\left(x \right)} = x \log{\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. 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)=log(x)g{\left(x \right)} = \log{\left(x \right)}; calculamos ddxg(x)\frac{d}{d x} g{\left(x \right)}:

      1. Derivado log(x)\log{\left(x \right)} es 1x\frac{1}{x}.

      Como resultado de: log(x)+1\log{\left(x \right)} + 1

    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:

    xlog(x)sin(x)+(log(x)+1)cos(x)cos2(x)\frac{x \log{\left(x \right)} \sin{\left(x \right)} + \left(\log{\left(x \right)} + 1\right) \cos{\left(x \right)}}{\cos^{2}{\left(x \right)}}

  2. Simplificamos:

    xlog(x)tan(x)+log(x)+1cos(x)\frac{x \log{\left(x \right)} \tan{\left(x \right)} + \log{\left(x \right)} + 1}{\cos{\left(x \right)}}


Respuesta:

xlog(x)tan(x)+log(x)+1cos(x)\frac{x \log{\left(x \right)} \tan{\left(x \right)} + \log{\left(x \right)} + 1}{\cos{\left(x \right)}}

Gráfica
02468-8-6-4-2-1010-1000010000
Primera derivada [src]
1 + log(x)   x*log(x)*sin(x)
---------- + ---------------
  cos(x)            2       
                 cos (x)    
xlog(x)sin(x)cos2(x)+log(x)+1cos(x)\frac{x \log{\left(x \right)} \sin{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{\log{\left(x \right)} + 1}{\cos{\left(x \right)}}
Segunda derivada [src]
      /         2   \                               
1     |    2*sin (x)|          2*(1 + log(x))*sin(x)
- + x*|1 + ---------|*log(x) + ---------------------
x     |        2    |                  cos(x)       
      \     cos (x) /                               
----------------------------------------------------
                       cos(x)                       
x(2sin2(x)cos2(x)+1)log(x)+2(log(x)+1)sin(x)cos(x)+1xcos(x)\frac{x \left(\frac{2 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1\right) \log{\left(x \right)} + \frac{2 \left(\log{\left(x \right)} + 1\right) \sin{\left(x \right)}}{\cos{\left(x \right)}} + \frac{1}{x}}{\cos{\left(x \right)}}
Tercera derivada [src]
                                                     /         2   \              
                                                     |    6*sin (x)|              
                                                   x*|5 + ---------|*log(x)*sin(x)
         /         2   \                             |        2    |              
  1      |    2*sin (x)|                3*sin(x)     \     cos (x) /              
- -- + 3*|1 + ---------|*(1 + log(x)) + -------- + -------------------------------
   2     |        2    |                x*cos(x)                cos(x)            
  x      \     cos (x) /                                                          
----------------------------------------------------------------------------------
                                      cos(x)                                      
x(6sin2(x)cos2(x)+5)log(x)sin(x)cos(x)+3(2sin2(x)cos2(x)+1)(log(x)+1)+3sin(x)xcos(x)1x2cos(x)\frac{\frac{x \left(\frac{6 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 5\right) \log{\left(x \right)} \sin{\left(x \right)}}{\cos{\left(x \right)}} + 3 \left(\frac{2 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1\right) \left(\log{\left(x \right)} + 1\right) + \frac{3 \sin{\left(x \right)}}{x \cos{\left(x \right)}} - \frac{1}{x^{2}}}{\cos{\left(x \right)}}
Gráfico
Derivada de x*lnx/cosx