Sr Examen

Derivada de y=2tgx/ctgx

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

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Solución

Ha introducido [src]
2*tan(x)
--------
 cot(x) 
2tan(x)cot(x)\frac{2 \tan{\left(x \right)}}{\cot{\left(x \right)}}
(2*tan(x))/cot(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)=2tan(x)f{\left(x \right)} = 2 \tan{\left(x \right)} y g(x)=cot(x)g{\left(x \right)} = \cot{\left(x \right)}.

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

    1. La derivada del producto de una constante por función es igual al producto de esta constante por la derivada de esta función.

      1. Reescribimos las funciones para diferenciar:

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

      2. 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)}}

      Entonces, como resultado: 2(sin2(x)+cos2(x))cos2(x)\frac{2 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right)}{\cos^{2}{\left(x \right)}}

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

    1. Hay varias formas de calcular esta derivada.

      Method #1

      1. Reescribimos las funciones para diferenciar:

        cot(x)=1tan(x)\cot{\left(x \right)} = \frac{1}{\tan{\left(x \right)}}

      2. Sustituimos u=tan(x)u = \tan{\left(x \right)}.

      3. Según el principio, aplicamos: 1u\frac{1}{u} tenemos 1u2- \frac{1}{u^{2}}

      4. Luego se aplica una cadena de reglas. Multiplicamos por ddxtan(x)\frac{d}{d x} \tan{\left(x \right)}:

        1. ddxtan(x)=1cos2(x)\frac{d}{d x} \tan{\left(x \right)} = \frac{1}{\cos^{2}{\left(x \right)}}

        Como resultado de la secuencia de reglas:

        sin2(x)+cos2(x)cos2(x)tan2(x)- \frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)} \tan^{2}{\left(x \right)}}

      Method #2

      1. Reescribimos las funciones para diferenciar:

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

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

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

        Para calcular 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)}

        Ahora aplicamos la regla de la derivada de una divesión:

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

    Ahora aplicamos la regla de la derivada de una divesión:

    2(sin2(x)+cos2(x))cot(x)cos2(x)+2(sin2(x)+cos2(x))cos2(x)tan(x)cot2(x)\frac{\frac{2 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right) \cot{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{2 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right)}{\cos^{2}{\left(x \right)} \tan{\left(x \right)}}}{\cot^{2}{\left(x \right)}}

  2. Simplificamos:

    4tan(x)cos2(x)\frac{4 \tan{\left(x \right)}}{\cos^{2}{\left(x \right)}}


Respuesta:

4tan(x)cos2(x)\frac{4 \tan{\left(x \right)}}{\cos^{2}{\left(x \right)}}

Gráfica
02468-8-6-4-2-1010-200000200000
Primera derivada [src]
         2        /       2   \       
2 + 2*tan (x)   2*\1 + cot (x)/*tan(x)
------------- + ----------------------
    cot(x)                2           
                       cot (x)        
2tan2(x)+2cot(x)+2(cot2(x)+1)tan(x)cot2(x)\frac{2 \tan^{2}{\left(x \right)} + 2}{\cot{\left(x \right)}} + \frac{2 \left(\cot^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}}{\cot^{2}{\left(x \right)}}
Segunda derivada [src]
  /                       /       2   \ /       2   \                 /            2   \       \
  |/       2   \          \1 + cot (x)/*\1 + tan (x)/   /       2   \ |     1 + cot (x)|       |
4*|\1 + tan (x)/*tan(x) + --------------------------- + \1 + cot (x)/*|-1 + -----------|*tan(x)|
  |                                  cot(x)                           |          2     |       |
  \                                                                   \       cot (x)  /       /
------------------------------------------------------------------------------------------------
                                             cot(x)                                             
4((cot2(x)+1cot2(x)1)(cot2(x)+1)tan(x)+(tan2(x)+1)(cot2(x)+1)cot(x)+(tan2(x)+1)tan(x))cot(x)\frac{4 \left(\left(\frac{\cot^{2}{\left(x \right)} + 1}{\cot^{2}{\left(x \right)}} - 1\right) \left(\cot^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)} + \frac{\left(\tan^{2}{\left(x \right)} + 1\right) \left(\cot^{2}{\left(x \right)} + 1\right)}{\cot{\left(x \right)}} + \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}\right)}{\cot{\left(x \right)}}
Tercera derivada [src]
  /                                                                                                                             /            2   \                                       \
  |                                                                                                 /       2   \ /       2   \ |     1 + cot (x)|                                       |
  |/                               2                  3\                                          3*\1 + cot (x)/*\1 + tan (x)/*|-1 + -----------|                                       |
  ||                  /       2   \      /       2   \ |          /       2   \ /         2   \                                 |          2     |     /       2   \ /       2   \       |
  ||         2      5*\1 + cot (x)/    3*\1 + cot (x)/ |          \1 + tan (x)/*\1 + 3*tan (x)/                                 \       cot (x)  /   3*\1 + cot (x)/*\1 + tan (x)/*tan(x)|
4*||2 + 2*cot (x) - ---------------- + ----------------|*tan(x) + ----------------------------- + ------------------------------------------------ + ------------------------------------|
  ||                       2                  4        |                      cot(x)                                   cot(x)                                         2                  |
  \\                    cot (x)            cot (x)     /                                                                                                           cot (x)               /
4(3(cot2(x)+1cot2(x)1)(tan2(x)+1)(cot2(x)+1)cot(x)+(tan2(x)+1)(3tan2(x)+1)cot(x)+3(tan2(x)+1)(cot2(x)+1)tan(x)cot2(x)+(3(cot2(x)+1)3cot4(x)5(cot2(x)+1)2cot2(x)+2cot2(x)+2)tan(x))4 \left(\frac{3 \left(\frac{\cot^{2}{\left(x \right)} + 1}{\cot^{2}{\left(x \right)}} - 1\right) \left(\tan^{2}{\left(x \right)} + 1\right) \left(\cot^{2}{\left(x \right)} + 1\right)}{\cot{\left(x \right)}} + \frac{\left(\tan^{2}{\left(x \right)} + 1\right) \left(3 \tan^{2}{\left(x \right)} + 1\right)}{\cot{\left(x \right)}} + \frac{3 \left(\tan^{2}{\left(x \right)} + 1\right) \left(\cot^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}}{\cot^{2}{\left(x \right)}} + \left(\frac{3 \left(\cot^{2}{\left(x \right)} + 1\right)^{3}}{\cot^{4}{\left(x \right)}} - \frac{5 \left(\cot^{2}{\left(x \right)} + 1\right)^{2}}{\cot^{2}{\left(x \right)}} + 2 \cot^{2}{\left(x \right)} + 2\right) \tan{\left(x \right)}\right)
Gráfico
Derivada de y=2tgx/ctgx