Sr Examen

Derivada de y=xtg^3x

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

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Solución

Ha introducido [src]
     3   
x*tan (x)
xtan3(x)x \tan^{3}{\left(x \right)}
x*tan(x)^3
Solución detallada
  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)=tan3(x)g{\left(x \right)} = \tan^{3}{\left(x \right)}; calculamos ddxg(x)\frac{d}{d x} g{\left(x \right)}:

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

    2. Según el principio, aplicamos: u3u^{3} tenemos 3u23 u^{2}

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

      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)}}

      Como resultado de la secuencia de reglas:

      3(sin2(x)+cos2(x))tan2(x)cos2(x)\frac{3 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right) \tan^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}}

    Como resultado de: 3x(sin2(x)+cos2(x))tan2(x)cos2(x)+tan3(x)\frac{3 x \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right) \tan^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \tan^{3}{\left(x \right)}

  2. Simplificamos:

    3xsin2(x)cos4(x)+tan3(x)\frac{3 x \sin^{2}{\left(x \right)}}{\cos^{4}{\left(x \right)}} + \tan^{3}{\left(x \right)}


Respuesta:

3xsin2(x)cos4(x)+tan3(x)\frac{3 x \sin^{2}{\left(x \right)}}{\cos^{4}{\left(x \right)}} + \tan^{3}{\left(x \right)}

Gráfica
02468-8-6-4-2-1010-2000000020000000
Primera derivada [src]
   3           2    /         2   \
tan (x) + x*tan (x)*\3 + 3*tan (x)/
x(3tan2(x)+3)tan2(x)+tan3(x)x \left(3 \tan^{2}{\left(x \right)} + 3\right) \tan^{2}{\left(x \right)} + \tan^{3}{\left(x \right)}
Segunda derivada [src]
  /       2   \ /  /         2   \         \       
6*\1 + tan (x)/*\x*\1 + 2*tan (x)/ + tan(x)/*tan(x)
6(x(2tan2(x)+1)+tan(x))(tan2(x)+1)tan(x)6 \left(x \left(2 \tan^{2}{\left(x \right)} + 1\right) + \tan{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}
Tercera derivada [src]
                /  /             2                                      \                           \
  /       2   \ |  |/       2   \         4           2    /       2   \|     /         2   \       |
6*\1 + tan (x)/*\x*\\1 + tan (x)/  + 2*tan (x) + 7*tan (x)*\1 + tan (x)// + 3*\1 + 2*tan (x)/*tan(x)/
6(x((tan2(x)+1)2+7(tan2(x)+1)tan2(x)+2tan4(x))+3(2tan2(x)+1)tan(x))(tan2(x)+1)6 \left(x \left(\left(\tan^{2}{\left(x \right)} + 1\right)^{2} + 7 \left(\tan^{2}{\left(x \right)} + 1\right) \tan^{2}{\left(x \right)} + 2 \tan^{4}{\left(x \right)}\right) + 3 \left(2 \tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 1\right)
3-я производная [src]
                /  /             2                                      \                           \
  /       2   \ |  |/       2   \         4           2    /       2   \|     /         2   \       |
6*\1 + tan (x)/*\x*\\1 + tan (x)/  + 2*tan (x) + 7*tan (x)*\1 + tan (x)// + 3*\1 + 2*tan (x)/*tan(x)/
6(x((tan2(x)+1)2+7(tan2(x)+1)tan2(x)+2tan4(x))+3(2tan2(x)+1)tan(x))(tan2(x)+1)6 \left(x \left(\left(\tan^{2}{\left(x \right)} + 1\right)^{2} + 7 \left(\tan^{2}{\left(x \right)} + 1\right) \tan^{2}{\left(x \right)} + 2 \tan^{4}{\left(x \right)}\right) + 3 \left(2 \tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 1\right)
Gráfico
Derivada de y=xtg^3x