Derivado de $$$x^{2} \sin{\left(x \right)}$$$
Calculadora relacionada: Calculadora de derivadas
Su opinión
Encuentre $$$\frac{d}{dx} \left(x^{2} \sin{\left(x \right)}\right)$$$.
Solución
Sea $$$H{\left(x \right)} = x^{2} \sin{\left(x \right)}$$$.
Tomemos el logaritmo de ambos lados: $$$\ln\left(H{\left(x \right)}\right) = \ln\left(x^{2} \sin{\left(x \right)}\right)$$$.
Reescribe el lado derecho utilizando las propiedades de los logaritmos: $$$\ln\left(H{\left(x \right)}\right) = 2 \ln\left(x\right) + \ln\left(\sin{\left(x \right)}\right)$$$.
Diferencia por separado ambos lados de la ecuación: $$$\frac{d}{dx} \left(\ln\left(H{\left(x \right)}\right)\right) = \frac{d}{dx} \left(2 \ln\left(x\right) + \ln\left(\sin{\left(x \right)}\right)\right)$$$.
Diferencia el lado izquierdo de la ecuación.
La función $$$\ln\left(H{\left(x \right)}\right)$$$ es la composición $$$f{\left(g{\left(x \right)} \right)}$$$ de dos funciones $$$f{\left(u \right)} = \ln\left(u\right)$$$ y $$$g{\left(x \right)} = H{\left(x \right)}$$$.
Aplique la regla de la cadena $$$\frac{d}{dx} \left(f{\left(g{\left(x \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dx} \left(g{\left(x \right)}\right)$$$:
$${\color{red}\left(\frac{d}{dx} \left(\ln\left(H{\left(x \right)}\right)\right)\right)} = {\color{red}\left(\frac{d}{du} \left(\ln\left(u\right)\right) \frac{d}{dx} \left(H{\left(x \right)}\right)\right)}$$La derivada del logaritmo natural es $$$\frac{d}{du} \left(\ln\left(u\right)\right) = \frac{1}{u}$$$:
$${\color{red}\left(\frac{d}{du} \left(\ln\left(u\right)\right)\right)} \frac{d}{dx} \left(H{\left(x \right)}\right) = {\color{red}\left(\frac{1}{u}\right)} \frac{d}{dx} \left(H{\left(x \right)}\right)$$Volver a la antigua variable:
$$\frac{\frac{d}{dx} \left(H{\left(x \right)}\right)}{{\color{red}\left(u\right)}} = \frac{\frac{d}{dx} \left(H{\left(x \right)}\right)}{{\color{red}\left(H{\left(x \right)}\right)}}$$Así, $$$\frac{d}{dx} \left(\ln\left(H{\left(x \right)}\right)\right) = \frac{\frac{d}{dx} \left(H{\left(x \right)}\right)}{H{\left(x \right)}}$$$.
Diferencia el lado derecho de la ecuación.
La derivada de una suma/diferencia es la suma/diferencia de derivadas:
$${\color{red}\left(\frac{d}{dx} \left(2 \ln\left(x\right) + \ln\left(\sin{\left(x \right)}\right)\right)\right)} = {\color{red}\left(\frac{d}{dx} \left(2 \ln\left(x\right)\right) + \frac{d}{dx} \left(\ln\left(\sin{\left(x \right)}\right)\right)\right)}$$Aplique la regla múltiple constante $$$\frac{d}{dx} \left(c f{\left(x \right)}\right) = c \frac{d}{dx} \left(f{\left(x \right)}\right)$$$ con $$$c = 2$$$ y $$$f{\left(x \right)} = \ln\left(x\right)$$$:
$${\color{red}\left(\frac{d}{dx} \left(2 \ln\left(x\right)\right)\right)} + \frac{d}{dx} \left(\ln\left(\sin{\left(x \right)}\right)\right) = {\color{red}\left(2 \frac{d}{dx} \left(\ln\left(x\right)\right)\right)} + \frac{d}{dx} \left(\ln\left(\sin{\left(x \right)}\right)\right)$$La derivada del logaritmo natural es $$$\frac{d}{dx} \left(\ln\left(x\right)\right) = \frac{1}{x}$$$:
$$2 {\color{red}\left(\frac{d}{dx} \left(\ln\left(x\right)\right)\right)} + \frac{d}{dx} \left(\ln\left(\sin{\left(x \right)}\right)\right) = 2 {\color{red}\left(\frac{1}{x}\right)} + \frac{d}{dx} \left(\ln\left(\sin{\left(x \right)}\right)\right)$$La función $$$\ln\left(\sin{\left(x \right)}\right)$$$ es la composición $$$f{\left(g{\left(x \right)} \right)}$$$ de dos funciones $$$f{\left(u \right)} = \ln\left(u\right)$$$ y $$$g{\left(x \right)} = \sin{\left(x \right)}$$$.
Aplique la regla de la cadena $$$\frac{d}{dx} \left(f{\left(g{\left(x \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dx} \left(g{\left(x \right)}\right)$$$:
$${\color{red}\left(\frac{d}{dx} \left(\ln\left(\sin{\left(x \right)}\right)\right)\right)} + \frac{2}{x} = {\color{red}\left(\frac{d}{du} \left(\ln\left(u\right)\right) \frac{d}{dx} \left(\sin{\left(x \right)}\right)\right)} + \frac{2}{x}$$La derivada del logaritmo natural es $$$\frac{d}{du} \left(\ln\left(u\right)\right) = \frac{1}{u}$$$:
$${\color{red}\left(\frac{d}{du} \left(\ln\left(u\right)\right)\right)} \frac{d}{dx} \left(\sin{\left(x \right)}\right) + \frac{2}{x} = {\color{red}\left(\frac{1}{u}\right)} \frac{d}{dx} \left(\sin{\left(x \right)}\right) + \frac{2}{x}$$Volver a la antigua variable:
$$\frac{\frac{d}{dx} \left(\sin{\left(x \right)}\right)}{{\color{red}\left(u\right)}} + \frac{2}{x} = \frac{\frac{d}{dx} \left(\sin{\left(x \right)}\right)}{{\color{red}\left(\sin{\left(x \right)}\right)}} + \frac{2}{x}$$La derivada del seno es $$$\frac{d}{dx} \left(\sin{\left(x \right)}\right) = \cos{\left(x \right)}$$$:
$$\frac{{\color{red}\left(\frac{d}{dx} \left(\sin{\left(x \right)}\right)\right)}}{\sin{\left(x \right)}} + \frac{2}{x} = \frac{{\color{red}\left(\cos{\left(x \right)}\right)}}{\sin{\left(x \right)}} + \frac{2}{x}$$Simplifica:
$$\frac{\cos{\left(x \right)}}{\sin{\left(x \right)}} + \frac{2}{x} = \frac{\frac{x}{\tan{\left(x \right)}} + 2}{x}$$Así, $$$\frac{d}{dx} \left(2 \ln\left(x\right) + \ln\left(\sin{\left(x \right)}\right)\right) = \frac{\frac{x}{\tan{\left(x \right)}} + 2}{x}$$$.
Por lo tanto, $$$\frac{\frac{d}{dx} \left(H{\left(x \right)}\right)}{H{\left(x \right)}} = \frac{\frac{x}{\tan{\left(x \right)}} + 2}{x}$$$.
Por lo tanto, $$$\frac{d}{dx} \left(H{\left(x \right)}\right) = \frac{\left(\frac{x}{\tan{\left(x \right)}} + 2\right) H{\left(x \right)}}{x} = x \left(x \cos{\left(x \right)} + 2 \sin{\left(x \right)}\right)$$$.
Respuesta
$$$\frac{d}{dx} \left(x^{2} \sin{\left(x \right)}\right) = x \left(x \cos{\left(x \right)} + 2 \sin{\left(x \right)}\right)$$$A