Sr Examen

Derivada de xsinx/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*sin(x)
--------
 cos(x) 
xsin(x)cos(x)\frac{x \sin{\left(x \right)}}{\cos{\left(x \right)}}
(x*sin(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)=xsin(x)f{\left(x \right)} = x \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. 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. 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:

    xsin2(x)+(xcos(x)+sin(x))cos(x)cos2(x)\frac{x \sin^{2}{\left(x \right)} + \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \cos{\left(x \right)}}{\cos^{2}{\left(x \right)}}

  2. Simplificamos:

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


Respuesta:

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

Gráfica
02468-8-6-4-2-1010-1000010000
Primera derivada [src]
                         2   
x*cos(x) + sin(x)   x*sin (x)
----------------- + ---------
      cos(x)            2    
                     cos (x) 
xsin2(x)cos2(x)+xcos(x)+sin(x)cos(x)\frac{x \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{x \cos{\left(x \right)} + \sin{\left(x \right)}}{\cos{\left(x \right)}}
Segunda derivada [src]
                        /         2   \                                      
                        |    2*sin (x)|          2*(x*cos(x) + sin(x))*sin(x)
2*cos(x) - x*sin(x) + x*|1 + ---------|*sin(x) + ----------------------------
                        |        2    |                     cos(x)           
                        \     cos (x) /                                      
-----------------------------------------------------------------------------
                                    cos(x)                                   
x(2sin2(x)cos2(x)+1)sin(x)xsin(x)+2(xcos(x)+sin(x))sin(x)cos(x)+2cos(x)cos(x)\frac{x \left(\frac{2 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1\right) \sin{\left(x \right)} - x \sin{\left(x \right)} + \frac{2 \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \sin{\left(x \right)}}{\cos{\left(x \right)}} + 2 \cos{\left(x \right)}}{\cos{\left(x \right)}}
Tercera derivada [src]
                                                                                                           /         2   \
                                                                                                      2    |    6*sin (x)|
                                                                                                 x*sin (x)*|5 + ---------|
                         /         2   \                                                                   |        2    |
                         |    2*sin (x)|                       3*(-2*cos(x) + x*sin(x))*sin(x)             \     cos (x) /
-3*sin(x) - x*cos(x) + 3*|1 + ---------|*(x*cos(x) + sin(x)) - ------------------------------- + -------------------------
                         |        2    |                                    cos(x)                         cos(x)         
                         \     cos (x) /                                                                                  
--------------------------------------------------------------------------------------------------------------------------
                                                          cos(x)                                                          
x(6sin2(x)cos2(x)+5)sin2(x)cos(x)xcos(x)3(xsin(x)2cos(x))sin(x)cos(x)+3(xcos(x)+sin(x))(2sin2(x)cos2(x)+1)3sin(x)cos(x)\frac{\frac{x \left(\frac{6 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 5\right) \sin^{2}{\left(x \right)}}{\cos{\left(x \right)}} - x \cos{\left(x \right)} - \frac{3 \left(x \sin{\left(x \right)} - 2 \cos{\left(x \right)}\right) \sin{\left(x \right)}}{\cos{\left(x \right)}} + 3 \left(x \cos{\left(x \right)} + \sin{\left(x \right)}\right) \left(\frac{2 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1\right) - 3 \sin{\left(x \right)}}{\cos{\left(x \right)}}
Gráfico
Derivada de xsinx/cosx