$$$\frac{2500 - 3 t}{t^{2}}$$$ 的積分
您的輸入
求$$$\int \frac{2500 - 3 t}{t^{2}}\, dt$$$。
解答
Expand the expression:
$${\color{red}{\int{\frac{2500 - 3 t}{t^{2}} d t}}} = {\color{red}{\int{\left(- \frac{3}{t} + \frac{2500}{t^{2}}\right)d t}}}$$
逐項積分：
$${\color{red}{\int{\left(- \frac{3}{t} + \frac{2500}{t^{2}}\right)d t}}} = {\color{red}{\left(\int{\frac{2500}{t^{2}} d t} - \int{\frac{3}{t} d t}\right)}}$$
套用常數倍法則 $$$\int c f{\left(t \right)}\, dt = c \int f{\left(t \right)}\, dt$$$，使用 $$$c=3$$$ 與 $$$f{\left(t \right)} = \frac{1}{t}$$$：
$$\int{\frac{2500}{t^{2}} d t} - {\color{red}{\int{\frac{3}{t} d t}}} = \int{\frac{2500}{t^{2}} d t} - {\color{red}{\left(3 \int{\frac{1}{t} d t}\right)}}$$
$$$\frac{1}{t}$$$ 的積分是 $$$\int{\frac{1}{t} d t} = \ln{\left(\left|{t}\right| \right)}$$$：
$$\int{\frac{2500}{t^{2}} d t} - 3 {\color{red}{\int{\frac{1}{t} d t}}} = \int{\frac{2500}{t^{2}} d t} - 3 {\color{red}{\ln{\left(\left|{t}\right| \right)}}}$$
套用常數倍法則 $$$\int c f{\left(t \right)}\, dt = c \int f{\left(t \right)}\, dt$$$，使用 $$$c=2500$$$ 與 $$$f{\left(t \right)} = \frac{1}{t^{2}}$$$：
$$- 3 \ln{\left(\left|{t}\right| \right)} + {\color{red}{\int{\frac{2500}{t^{2}} d t}}} = - 3 \ln{\left(\left|{t}\right| \right)} + {\color{red}{\left(2500 \int{\frac{1}{t^{2}} d t}\right)}}$$
套用冪次法則 $$$\int t^{n}\, dt = \frac{t^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$，以 $$$n=-2$$$：
$$- 3 \ln{\left(\left|{t}\right| \right)} + 2500 {\color{red}{\int{\frac{1}{t^{2}} d t}}}=- 3 \ln{\left(\left|{t}\right| \right)} + 2500 {\color{red}{\int{t^{-2} d t}}}=- 3 \ln{\left(\left|{t}\right| \right)} + 2500 {\color{red}{\frac{t^{-2 + 1}}{-2 + 1}}}=- 3 \ln{\left(\left|{t}\right| \right)} + 2500 {\color{red}{\left(- t^{-1}\right)}}=- 3 \ln{\left(\left|{t}\right| \right)} + 2500 {\color{red}{\left(- \frac{1}{t}\right)}}$$
因此，
$$\int{\frac{2500 - 3 t}{t^{2}} d t} = - 3 \ln{\left(\left|{t}\right| \right)} - \frac{2500}{t}$$
加上積分常數：
$$\int{\frac{2500 - 3 t}{t^{2}} d t} = - 3 \ln{\left(\left|{t}\right| \right)} - \frac{2500}{t}+C$$
答案
$$$\int \frac{2500 - 3 t}{t^{2}}\, dt = \left(- 3 \ln\left(\left|{t}\right|\right) - \frac{2500}{t}\right) + C$$$A