$$$\frac{16 x - 9}{x}$$$ 的積分

求$$$\int \frac{16 x - 9}{x}\, dx$$$。

Expand the expression:

$${\color{red}{\int{\frac{16 x - 9}{x} d x}}} = {\color{red}{\int{\left(16 - \frac{9}{x}\right)d x}}}$$

逐項積分：

$${\color{red}{\int{\left(16 - \frac{9}{x}\right)d x}}} = {\color{red}{\left(\int{16 d x} - \int{\frac{9}{x} d x}\right)}}$$

配合 $$$c=16$$$，應用常數法則 $$$\int c\, dx = c x$$$：

$$- \int{\frac{9}{x} d x} + {\color{red}{\int{16 d x}}} = - \int{\frac{9}{x} d x} + {\color{red}{\left(16 x\right)}}$$

套用常數倍法則 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$，使用 $$$c=9$$$ 與 $$$f{\left(x \right)} = \frac{1}{x}$$$：

$$16 x - {\color{red}{\int{\frac{9}{x} d x}}} = 16 x - {\color{red}{\left(9 \int{\frac{1}{x} d x}\right)}}$$

$$$\frac{1}{x}$$$ 的積分是 $$$\int{\frac{1}{x} d x} = \ln{\left(\left|{x}\right| \right)}$$$：

$$16 x - 9 {\color{red}{\int{\frac{1}{x} d x}}} = 16 x - 9 {\color{red}{\ln{\left(\left|{x}\right| \right)}}}$$

因此，

$$\int{\frac{16 x - 9}{x} d x} = 16 x - 9 \ln{\left(\left|{x}\right| \right)}$$

加上積分常數：

$$\int{\frac{16 x - 9}{x} d x} = 16 x - 9 \ln{\left(\left|{x}\right| \right)}+C$$

$$$\int \frac{16 x - 9}{x}\, dx = \left(16 x - 9 \ln\left(\left|{x}\right|\right)\right) + C$$$A