Integral de $$$18 x^{2} - 9$$$

Encontre $$$\int \left(18 x^{2} - 9\right)\, dx$$$.

Integre termo a termo:

$${\color{red}{\int{\left(18 x^{2} - 9\right)d x}}} = {\color{red}{\left(- \int{9 d x} + \int{18 x^{2} d x}\right)}}$$

Aplique a regra da constante $$$\int c\, dx = c x$$$ usando $$$c=9$$$:

$$\int{18 x^{2} d x} - {\color{red}{\int{9 d x}}} = \int{18 x^{2} d x} - {\color{red}{\left(9 x\right)}}$$

Aplique a regra do múltiplo constante $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ usando $$$c=18$$$ e $$$f{\left(x \right)} = x^{2}$$$:

$$- 9 x + {\color{red}{\int{18 x^{2} d x}}} = - 9 x + {\color{red}{\left(18 \int{x^{2} d x}\right)}}$$

Aplique a regra da potência $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ com $$$n=2$$$:

$$- 9 x + 18 {\color{red}{\int{x^{2} d x}}}=- 9 x + 18 {\color{red}{\frac{x^{1 + 2}}{1 + 2}}}=- 9 x + 18 {\color{red}{\left(\frac{x^{3}}{3}\right)}}$$

Portanto,

$$\int{\left(18 x^{2} - 9\right)d x} = 6 x^{3} - 9 x$$

Adicione a constante de integração:

$$\int{\left(18 x^{2} - 9\right)d x} = 6 x^{3} - 9 x+C$$

$$$\int \left(18 x^{2} - 9\right)\, dx = \left(6 x^{3} - 9 x\right) + C$$$A