Integral de $$$\frac{1}{\sqrt{x} \csc{\left(\sqrt{x} \right)}}$$$

Encontre $$$\int \frac{1}{\sqrt{x} \csc{\left(\sqrt{x} \right)}}\, dx$$$.

Seja $$$u=\sqrt{x}$$$.

Então $$$du=\left(\sqrt{x}\right)^{\prime }dx = \frac{1}{2 \sqrt{x}} dx$$$ (veja os passos »), e obtemos $$$\frac{dx}{\sqrt{x}} = 2 du$$$.

Portanto,

$${\color{red}{\int{\frac{1}{\sqrt{x} \csc{\left(\sqrt{x} \right)}} d x}}} = {\color{red}{\int{\frac{2}{\csc{\left(u \right)}} d u}}}$$

Aplique a regra do múltiplo constante $$$\int c f{\left(u \right)}\, du = c \int f{\left(u \right)}\, du$$$ usando $$$c=2$$$ e $$$f{\left(u \right)} = \frac{1}{\csc{\left(u \right)}}$$$:

$${\color{red}{\int{\frac{2}{\csc{\left(u \right)}} d u}}} = {\color{red}{\left(2 \int{\frac{1}{\csc{\left(u \right)}} d u}\right)}}$$

Reescreva o integrando em termos do seno:

$$2 {\color{red}{\int{\frac{1}{\csc{\left(u \right)}} d u}}} = 2 {\color{red}{\int{\sin{\left(u \right)} d u}}}$$

A integral do seno é $$$\int{\sin{\left(u \right)} d u} = - \cos{\left(u \right)}$$$:

$$2 {\color{red}{\int{\sin{\left(u \right)} d u}}} = 2 {\color{red}{\left(- \cos{\left(u \right)}\right)}}$$

Recorde que $$$u=\sqrt{x}$$$:

$$- 2 \cos{\left({\color{red}{u}} \right)} = - 2 \cos{\left({\color{red}{\sqrt{x}}} \right)}$$

Portanto,

$$\int{\frac{1}{\sqrt{x} \csc{\left(\sqrt{x} \right)}} d x} = - 2 \cos{\left(\sqrt{x} \right)}$$

Adicione a constante de integração:

$$\int{\frac{1}{\sqrt{x} \csc{\left(\sqrt{x} \right)}} d x} = - 2 \cos{\left(\sqrt{x} \right)}+C$$

$$$\int \frac{1}{\sqrt{x} \csc{\left(\sqrt{x} \right)}}\, dx = - 2 \cos{\left(\sqrt{x} \right)} + C$$$A