$$$\sin{\left(x \right)} - \pi$$$ 的積分

求$$$\int \left(\sin{\left(x \right)} - \pi\right)\, dx$$$。

逐項積分：

$${\color{red}{\int{\left(\sin{\left(x \right)} - \pi\right)d x}}} = {\color{red}{\left(- \int{\pi d x} + \int{\sin{\left(x \right)} d x}\right)}}$$

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

$$\int{\sin{\left(x \right)} d x} - {\color{red}{\int{\pi d x}}} = \int{\sin{\left(x \right)} d x} - {\color{red}{\pi x}}$$

正弦函數的積分為 $$$\int{\sin{\left(x \right)} d x} = - \cos{\left(x \right)}$$$：

$$- \pi x + {\color{red}{\int{\sin{\left(x \right)} d x}}} = - \pi x + {\color{red}{\left(- \cos{\left(x \right)}\right)}}$$

因此，

$$\int{\left(\sin{\left(x \right)} - \pi\right)d x} = - \pi x - \cos{\left(x \right)}$$

加上積分常數：

$$\int{\left(\sin{\left(x \right)} - \pi\right)d x} = - \pi x - \cos{\left(x \right)}+C$$

$$$\int \left(\sin{\left(x \right)} - \pi\right)\, dx = \left(- \pi x - \cos{\left(x \right)}\right) + C$$$A