Sr Examen

Derivada de y=lnsin3x/lnsinx

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

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Solución

Ha introducido [src]
log(sin(3*x))       
-------------*sin(x)
    log(x)          
log(sin(3x))log(x)sin(x)\frac{\log{\left(\sin{\left(3 x \right)} \right)}}{\log{\left(x \right)}} \sin{\left(x \right)}
(log(sin(3*x))/log(x))*sin(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)=log(sin(3x))sin(x)f{\left(x \right)} = \log{\left(\sin{\left(3 x \right)} \right)} \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)=log(sin(3x))f{\left(x \right)} = \log{\left(\sin{\left(3 x \right)} \right)}; calculamos ddxf(x)\frac{d}{d x} f{\left(x \right)}:

      1. Sustituimos u=sin(3x)u = \sin{\left(3 x \right)}.

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

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

        1. Sustituimos u=3xu = 3 x.

        2. La derivada del seno es igual al coseno:

          ddusin(u)=cos(u)\frac{d}{d u} \sin{\left(u \right)} = \cos{\left(u \right)}

        3. Luego se aplica una cadena de reglas. Multiplicamos por ddx3x\frac{d}{d x} 3 x:

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

            1. Según el principio, aplicamos: xx tenemos 11

            Entonces, como resultado: 33

          Como resultado de la secuencia de reglas:

          3cos(3x)3 \cos{\left(3 x \right)}

        Como resultado de la secuencia de reglas:

        3cos(3x)sin(3x)\frac{3 \cos{\left(3 x \right)}}{\sin{\left(3 x \right)}}

      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: log(sin(3x))cos(x)+3sin(x)cos(3x)sin(3x)\log{\left(\sin{\left(3 x \right)} \right)} \cos{\left(x \right)} + \frac{3 \sin{\left(x \right)} \cos{\left(3 x \right)}}{\sin{\left(3 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:

    (log(sin(3x))cos(x)+3sin(x)cos(3x)sin(3x))log(x)log(sin(3x))sin(x)xlog(x)2\frac{\left(\log{\left(\sin{\left(3 x \right)} \right)} \cos{\left(x \right)} + \frac{3 \sin{\left(x \right)} \cos{\left(3 x \right)}}{\sin{\left(3 x \right)}}\right) \log{\left(x \right)} - \frac{\log{\left(\sin{\left(3 x \right)} \right)} \sin{\left(x \right)}}{x}}{\log{\left(x \right)}^{2}}

  2. Simplificamos:

    log(sin(3x))cos(x)log(x)+3sin(x)log(x)tan(3x)log(sin(3x))sin(x)xlog(x)2\frac{\log{\left(\sin{\left(3 x \right)} \right)} \cos{\left(x \right)}}{\log{\left(x \right)}} + \frac{3 \sin{\left(x \right)}}{\log{\left(x \right)} \tan{\left(3 x \right)}} - \frac{\log{\left(\sin{\left(3 x \right)} \right)} \sin{\left(x \right)}}{x \log{\left(x \right)}^{2}}


Respuesta:

log(sin(3x))cos(x)log(x)+3sin(x)log(x)tan(3x)log(sin(3x))sin(x)xlog(x)2\frac{\log{\left(\sin{\left(3 x \right)} \right)} \cos{\left(x \right)}}{\log{\left(x \right)}} + \frac{3 \sin{\left(x \right)}}{\log{\left(x \right)} \tan{\left(3 x \right)}} - \frac{\log{\left(\sin{\left(3 x \right)} \right)} \sin{\left(x \right)}}{x \log{\left(x \right)}^{2}}

Gráfica
02468-8-6-4-2-1010-200200
Primera derivada [src]
/  log(sin(3*x))      3*cos(3*x)  \          cos(x)*log(sin(3*x))
|- ------------- + ---------------|*sin(x) + --------------------
|         2        log(x)*sin(3*x)|                 log(x)       
\    x*log (x)                    /                              
(3cos(3x)log(x)sin(3x)log(sin(3x))xlog(x)2)sin(x)+log(sin(3x))cos(x)log(x)\left(\frac{3 \cos{\left(3 x \right)}}{\log{\left(x \right)} \sin{\left(3 x \right)}} - \frac{\log{\left(\sin{\left(3 x \right)} \right)}}{x \log{\left(x \right)}^{2}}\right) \sin{\left(x \right)} + \frac{\log{\left(\sin{\left(3 x \right)} \right)} \cos{\left(x \right)}}{\log{\left(x \right)}}
Segunda derivada [src]
  /                  /      2   \                                  \                                                                      
  |         2        |1 + ------|*log(sin(3*x))                    |                                                                      
  |    9*cos (3*x)   \    log(x)/                     6*cos(3*x)   |                                   /3*cos(3*x)   log(sin(3*x))\       
- |9 + ----------- - -------------------------- + -----------------|*sin(x) - log(sin(3*x))*sin(x) + 2*|---------- - -------------|*cos(x)
  |        2                  2                   x*log(x)*sin(3*x)|                                   \ sin(3*x)       x*log(x)  /       
  \     sin (3*x)            x *log(x)                             /                                                                      
------------------------------------------------------------------------------------------------------------------------------------------
                                                                  log(x)                                                                  
2(3cos(3x)sin(3x)log(sin(3x))xlog(x))cos(x)(9+9cos2(3x)sin2(3x)+6cos(3x)xlog(x)sin(3x)(1+2log(x))log(sin(3x))x2log(x))sin(x)log(sin(3x))sin(x)log(x)\frac{2 \left(\frac{3 \cos{\left(3 x \right)}}{\sin{\left(3 x \right)}} - \frac{\log{\left(\sin{\left(3 x \right)} \right)}}{x \log{\left(x \right)}}\right) \cos{\left(x \right)} - \left(9 + \frac{9 \cos^{2}{\left(3 x \right)}}{\sin^{2}{\left(3 x \right)}} + \frac{6 \cos{\left(3 x \right)}}{x \log{\left(x \right)} \sin{\left(3 x \right)}} - \frac{\left(1 + \frac{2}{\log{\left(x \right)}}\right) \log{\left(\sin{\left(3 x \right)} \right)}}{x^{2} \log{\left(x \right)}}\right) \sin{\left(x \right)} - \log{\left(\sin{\left(3 x \right)} \right)} \sin{\left(x \right)}}{\log{\left(x \right)}}
Tercera derivada [src]
/   /       2     \      /       2     \                                                                            \                                                                                                                                                    
|   |    cos (3*x)|      |    cos (3*x)|              /      3         3   \                                        |                                                                                                                                                    
|27*|1 + ---------|   54*|1 + ---------|*cos(3*x)   2*|1 + ------ + -------|*log(sin(3*x))     /      2   \         |                                                                           /                  /      2   \                                  \       
|   |       2     |      |       2     |              |    log(x)      2   |                 9*|1 + ------|*cos(3*x)|                                                                           |         2        |1 + ------|*log(sin(3*x))                    |       
|   \    sin (3*x)/      \    sin (3*x)/              \             log (x)/                   \    log(x)/         |                                   /3*cos(3*x)   log(sin(3*x))\            |    9*cos (3*x)   \    log(x)/                     6*cos(3*x)   |       
|------------------ + --------------------------- - -------------------------------------- + -----------------------|*sin(x) - cos(x)*log(sin(3*x)) - 3*|---------- - -------------|*sin(x) - 3*|9 + ----------- - -------------------------- + -----------------|*cos(x)
|     x*log(x)                  sin(3*x)                           3                             2                  |                                   \ sin(3*x)       x*log(x)  /            |        2                  2                   x*log(x)*sin(3*x)|       
\                                                                 x *log(x)                     x *log(x)*sin(3*x)  /                                                                           \     sin (3*x)            x *log(x)                             /       
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                  log(x)                                                                                                                                 
3(3cos(3x)sin(3x)log(sin(3x))xlog(x))sin(x)3(9+9cos2(3x)sin2(3x)+6cos(3x)xlog(x)sin(3x)(1+2log(x))log(sin(3x))x2log(x))cos(x)+(54(1+cos2(3x)sin2(3x))cos(3x)sin(3x)+27(1+cos2(3x)sin2(3x))xlog(x)+9(1+2log(x))cos(3x)x2log(x)sin(3x)2(1+3log(x)+3log(x)2)log(sin(3x))x3log(x))sin(x)log(sin(3x))cos(x)log(x)\frac{- 3 \left(\frac{3 \cos{\left(3 x \right)}}{\sin{\left(3 x \right)}} - \frac{\log{\left(\sin{\left(3 x \right)} \right)}}{x \log{\left(x \right)}}\right) \sin{\left(x \right)} - 3 \left(9 + \frac{9 \cos^{2}{\left(3 x \right)}}{\sin^{2}{\left(3 x \right)}} + \frac{6 \cos{\left(3 x \right)}}{x \log{\left(x \right)} \sin{\left(3 x \right)}} - \frac{\left(1 + \frac{2}{\log{\left(x \right)}}\right) \log{\left(\sin{\left(3 x \right)} \right)}}{x^{2} \log{\left(x \right)}}\right) \cos{\left(x \right)} + \left(\frac{54 \left(1 + \frac{\cos^{2}{\left(3 x \right)}}{\sin^{2}{\left(3 x \right)}}\right) \cos{\left(3 x \right)}}{\sin{\left(3 x \right)}} + \frac{27 \left(1 + \frac{\cos^{2}{\left(3 x \right)}}{\sin^{2}{\left(3 x \right)}}\right)}{x \log{\left(x \right)}} + \frac{9 \left(1 + \frac{2}{\log{\left(x \right)}}\right) \cos{\left(3 x \right)}}{x^{2} \log{\left(x \right)} \sin{\left(3 x \right)}} - \frac{2 \left(1 + \frac{3}{\log{\left(x \right)}} + \frac{3}{\log{\left(x \right)}^{2}}\right) \log{\left(\sin{\left(3 x \right)} \right)}}{x^{3} \log{\left(x \right)}}\right) \sin{\left(x \right)} - \log{\left(\sin{\left(3 x \right)} \right)} \cos{\left(x \right)}}{\log{\left(x \right)}}
Gráfico
Derivada de y=lnsin3x/lnsinx