解答正弦函数的积分为 $$$\int{\sin{\left(x \right)} d x} = - \cos{\left(x \right)}$$$:

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

因此，

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

加上积分常数：

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