$$$\frac{\sqrt{2} \left(x^{2} - 25\right)}{x}$$$の積分

$$$\int \frac{\sqrt{2} \left(x^{2} - 25\right)}{x}\, dx$$$ を求めよ。

Expand the expression:

$${\color{red}{\int{\frac{\sqrt{2} \left(x^{2} - 25\right)}{x} d x}}} = {\color{red}{\int{\left(\sqrt{2} x - \frac{25 \sqrt{2}}{x}\right)d x}}}$$

項別に積分せよ:

$${\color{red}{\int{\left(\sqrt{2} x - \frac{25 \sqrt{2}}{x}\right)d x}}} = {\color{red}{\left(- \int{\frac{25 \sqrt{2}}{x} d x} + \int{\sqrt{2} x d x}\right)}}$$

定数倍の法則 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ を、$$$c=\sqrt{2}$$$ と $$$f{\left(x \right)} = x$$$ に対して適用する:

$$- \int{\frac{25 \sqrt{2}}{x} d x} + {\color{red}{\int{\sqrt{2} x d x}}} = - \int{\frac{25 \sqrt{2}}{x} d x} + {\color{red}{\sqrt{2} \int{x d x}}}$$

$$$n=1$$$ を用いて、べき乗の法則 $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ を適用します:

$$- \int{\frac{25 \sqrt{2}}{x} d x} + \sqrt{2} {\color{red}{\int{x d x}}}=- \int{\frac{25 \sqrt{2}}{x} d x} + \sqrt{2} {\color{red}{\frac{x^{1 + 1}}{1 + 1}}}=- \int{\frac{25 \sqrt{2}}{x} d x} + \sqrt{2} {\color{red}{\left(\frac{x^{2}}{2}\right)}}$$

定数倍の法則 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ を、$$$c=25 \sqrt{2}$$$ と $$$f{\left(x \right)} = \frac{1}{x}$$$ に対して適用する:

$$\frac{\sqrt{2} x^{2}}{2} - {\color{red}{\int{\frac{25 \sqrt{2}}{x} d x}}} = \frac{\sqrt{2} x^{2}}{2} - {\color{red}{\left(25 \sqrt{2} \int{\frac{1}{x} d x}\right)}}$$

$$$\frac{1}{x}$$$ の不定積分は $$$\int{\frac{1}{x} d x} = \ln{\left(\left|{x}\right| \right)}$$$ です:

$$\frac{\sqrt{2} x^{2}}{2} - 25 \sqrt{2} {\color{red}{\int{\frac{1}{x} d x}}} = \frac{\sqrt{2} x^{2}}{2} - 25 \sqrt{2} {\color{red}{\ln{\left(\left|{x}\right| \right)}}}$$

したがって、

$$\int{\frac{\sqrt{2} \left(x^{2} - 25\right)}{x} d x} = \frac{\sqrt{2} x^{2}}{2} - 25 \sqrt{2} \ln{\left(\left|{x}\right| \right)}$$

簡単化せよ:

$$\int{\frac{\sqrt{2} \left(x^{2} - 25\right)}{x} d x} = \frac{\sqrt{2} \left(x^{2} - 50 \ln{\left(\left|{x}\right| \right)}\right)}{2}$$

積分定数を加える:

$$\int{\frac{\sqrt{2} \left(x^{2} - 25\right)}{x} d x} = \frac{\sqrt{2} \left(x^{2} - 50 \ln{\left(\left|{x}\right| \right)}\right)}{2}+C$$

$$$\int \frac{\sqrt{2} \left(x^{2} - 25\right)}{x}\, dx = \frac{\sqrt{2} \left(x^{2} - 50 \ln\left(\left|{x}\right|\right)\right)}{2} + C$$$A