$$$3 x - \frac{1}{x^{22}}$$$ 的積分
您的輸入
求$$$\int \left(3 x - \frac{1}{x^{22}}\right)\, dx$$$。
解答
逐項積分：
$${\color{red}{\int{\left(3 x - \frac{1}{x^{22}}\right)d x}}} = {\color{red}{\left(- \int{\frac{1}{x^{22}} d x} + \int{3 x d x}\right)}}$$
套用冪次法則 $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$，以 $$$n=-22$$$：
$$\int{3 x d x} - {\color{red}{\int{\frac{1}{x^{22}} d x}}}=\int{3 x d x} - {\color{red}{\int{x^{-22} d x}}}=\int{3 x d x} - {\color{red}{\frac{x^{-22 + 1}}{-22 + 1}}}=\int{3 x d x} - {\color{red}{\left(- \frac{x^{-21}}{21}\right)}}=\int{3 x d x} - {\color{red}{\left(- \frac{1}{21 x^{21}}\right)}}$$
套用常數倍法則 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$，使用 $$$c=3$$$ 與 $$$f{\left(x \right)} = x$$$：
$${\color{red}{\int{3 x d x}}} + \frac{1}{21 x^{21}} = {\color{red}{\left(3 \int{x d x}\right)}} + \frac{1}{21 x^{21}}$$
套用冪次法則 $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$，以 $$$n=1$$$：
$$3 {\color{red}{\int{x d x}}} + \frac{1}{21 x^{21}}=3 {\color{red}{\frac{x^{1 + 1}}{1 + 1}}} + \frac{1}{21 x^{21}}=3 {\color{red}{\left(\frac{x^{2}}{2}\right)}} + \frac{1}{21 x^{21}}$$
因此，
$$\int{\left(3 x - \frac{1}{x^{22}}\right)d x} = \frac{3 x^{2}}{2} + \frac{1}{21 x^{21}}$$
化簡：
$$\int{\left(3 x - \frac{1}{x^{22}}\right)d x} = \frac{63 x^{23} + 2}{42 x^{21}}$$
加上積分常數：
$$\int{\left(3 x - \frac{1}{x^{22}}\right)d x} = \frac{63 x^{23} + 2}{42 x^{21}}+C$$
答案
$$$\int \left(3 x - \frac{1}{x^{22}}\right)\, dx = \frac{63 x^{23} + 2}{42 x^{21}} + C$$$A