Segunda derivada de $$$\tanh{\left(x \right)}$$$
Calculadoras relacionadas: Calculadora de Derivadas, Calculadora de Derivação Logarítmica
Sua entrada
Encontre $$$\frac{d^{2}}{dx^{2}} \left(\tanh{\left(x \right)}\right)$$$.
Solução
Encontre a primeira derivada $$$\frac{d}{dx} \left(\tanh{\left(x \right)}\right)$$$
A derivada da tangente hiperbólica é $$$\frac{d}{dx} \left(\tanh{\left(x \right)}\right) = \operatorname{sech}^{2}{\left(x \right)}$$$:
$${\color{red}\left(\frac{d}{dx} \left(\tanh{\left(x \right)}\right)\right)} = {\color{red}\left(\operatorname{sech}^{2}{\left(x \right)}\right)}$$Logo, $$$\frac{d}{dx} \left(\tanh{\left(x \right)}\right) = \operatorname{sech}^{2}{\left(x \right)}$$$.
Em seguida, $$$\frac{d^{2}}{dx^{2}} \left(\tanh{\left(x \right)}\right) = \frac{d}{dx} \left(\operatorname{sech}^{2}{\left(x \right)}\right)$$$
A função $$$\operatorname{sech}^{2}{\left(x \right)}$$$ é a composição $$$f{\left(g{\left(x \right)} \right)}$$$ de duas funções $$$f{\left(u \right)} = u^{2}$$$ e $$$g{\left(x \right)} = \operatorname{sech}{\left(x \right)}$$$.
Aplique a regra da cadeia $$$\frac{d}{dx} \left(f{\left(g{\left(x \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dx} \left(g{\left(x \right)}\right)$$$:
$${\color{red}\left(\frac{d}{dx} \left(\operatorname{sech}^{2}{\left(x \right)}\right)\right)} = {\color{red}\left(\frac{d}{du} \left(u^{2}\right) \frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right)\right)}$$Aplique a regra da potência $$$\frac{d}{du} \left(u^{n}\right) = n u^{n - 1}$$$ com $$$n = 2$$$:
$${\color{red}\left(\frac{d}{du} \left(u^{2}\right)\right)} \frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right) = {\color{red}\left(2 u\right)} \frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right)$$Retorne à variável original:
$$2 {\color{red}\left(u\right)} \frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right) = 2 {\color{red}\left(\operatorname{sech}{\left(x \right)}\right)} \frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right)$$A derivada da secante hiperbólica é $$$\frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right) = - \tanh{\left(x \right)} \operatorname{sech}{\left(x \right)}$$$:
$$2 \operatorname{sech}{\left(x \right)} {\color{red}\left(\frac{d}{dx} \left(\operatorname{sech}{\left(x \right)}\right)\right)} = 2 \operatorname{sech}{\left(x \right)} {\color{red}\left(- \tanh{\left(x \right)} \operatorname{sech}{\left(x \right)}\right)}$$Logo, $$$\frac{d}{dx} \left(\operatorname{sech}^{2}{\left(x \right)}\right) = - 2 \tanh{\left(x \right)} \operatorname{sech}^{2}{\left(x \right)}.$$$
Portanto, $$$\frac{d^{2}}{dx^{2}} \left(\tanh{\left(x \right)}\right) = - 2 \tanh{\left(x \right)} \operatorname{sech}^{2}{\left(x \right)}$$$.
Resposta
$$$\frac{d^{2}}{dx^{2}} \left(\tanh{\left(x \right)}\right) = - 2 \tanh{\left(x \right)} \operatorname{sech}^{2}{\left(x \right)}$$$A