$$$- \frac{\sin{\left(x \right)}}{x}$$$ 的积分
您的输入
求$$$\int \left(- \frac{\sin{\left(x \right)}}{x}\right)\, dx$$$。
解答
对 $$$c=-1$$$ 和 $$$f{\left(x \right)} = \frac{\sin{\left(x \right)}}{x}$$$ 应用常数倍法则 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$：
$${\color{red}{\int{\left(- \frac{\sin{\left(x \right)}}{x}\right)d x}}} = {\color{red}{\left(- \int{\frac{\sin{\left(x \right)}}{x} d x}\right)}}$$
该积分（正弦积分）没有闭式表达式：
$$- {\color{red}{\int{\frac{\sin{\left(x \right)}}{x} d x}}} = - {\color{red}{\operatorname{Si}{\left(x \right)}}}$$
因此，
$$\int{\left(- \frac{\sin{\left(x \right)}}{x}\right)d x} = - \operatorname{Si}{\left(x \right)}$$
加上积分常数：
$$\int{\left(- \frac{\sin{\left(x \right)}}{x}\right)d x} = - \operatorname{Si}{\left(x \right)}+C$$
答案
$$$\int \left(- \frac{\sin{\left(x \right)}}{x}\right)\, dx = - \operatorname{Si}{\left(x \right)} + C$$$A