$$$\frac{1}{4} - 5 \cos{\left(x \right)}$$$ 的積分
您的輸入
求$$$\int \left(\frac{1}{4} - 5 \cos{\left(x \right)}\right)\, dx$$$。
解答
逐項積分：
$${\color{red}{\int{\left(\frac{1}{4} - 5 \cos{\left(x \right)}\right)d x}}} = {\color{red}{\left(\int{\frac{1}{4} d x} - \int{5 \cos{\left(x \right)} d x}\right)}}$$
配合 $$$c=\frac{1}{4}$$$，應用常數法則 $$$\int c\, dx = c x$$$：
$$- \int{5 \cos{\left(x \right)} d x} + {\color{red}{\int{\frac{1}{4} d x}}} = - \int{5 \cos{\left(x \right)} d x} + {\color{red}{\left(\frac{x}{4}\right)}}$$
套用常數倍法則 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$，使用 $$$c=5$$$ 與 $$$f{\left(x \right)} = \cos{\left(x \right)}$$$：
$$\frac{x}{4} - {\color{red}{\int{5 \cos{\left(x \right)} d x}}} = \frac{x}{4} - {\color{red}{\left(5 \int{\cos{\left(x \right)} d x}\right)}}$$
餘弦函數的積分為 $$$\int{\cos{\left(x \right)} d x} = \sin{\left(x \right)}$$$：
$$\frac{x}{4} - 5 {\color{red}{\int{\cos{\left(x \right)} d x}}} = \frac{x}{4} - 5 {\color{red}{\sin{\left(x \right)}}}$$
因此，
$$\int{\left(\frac{1}{4} - 5 \cos{\left(x \right)}\right)d x} = \frac{x}{4} - 5 \sin{\left(x \right)}$$
加上積分常數：
$$\int{\left(\frac{1}{4} - 5 \cos{\left(x \right)}\right)d x} = \frac{x}{4} - 5 \sin{\left(x \right)}+C$$
答案
$$$\int \left(\frac{1}{4} - 5 \cos{\left(x \right)}\right)\, dx = \left(\frac{x}{4} - 5 \sin{\left(x \right)}\right) + C$$$A