$$$\frac{\sqrt{21} \sqrt{x^{3}}}{21}$$$ 的積分
您的輸入
求$$$\int \frac{\sqrt{21} \sqrt{x^{3}}}{21}\, dx$$$。
解答
已將輸入重寫為：$$$\int{\frac{\sqrt{21} \sqrt{x^{3}}}{21} d x}=\int{\frac{\sqrt{21} x^{\frac{3}{2}}}{21} d x}$$$。
套用常數倍法則 $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$，使用 $$$c=\frac{\sqrt{21}}{21}$$$ 與 $$$f{\left(x \right)} = x^{\frac{3}{2}}$$$：
$${\color{red}{\int{\frac{\sqrt{21} x^{\frac{3}{2}}}{21} d x}}} = {\color{red}{\left(\frac{\sqrt{21} \int{x^{\frac{3}{2}} d x}}{21}\right)}}$$
套用冪次法則 $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$，以 $$$n=\frac{3}{2}$$$：
$$\frac{\sqrt{21} {\color{red}{\int{x^{\frac{3}{2}} d x}}}}{21}=\frac{\sqrt{21} {\color{red}{\frac{x^{1 + \frac{3}{2}}}{1 + \frac{3}{2}}}}}{21}=\frac{\sqrt{21} {\color{red}{\left(\frac{2 x^{\frac{5}{2}}}{5}\right)}}}{21}$$
因此，
$$\int{\frac{\sqrt{21} x^{\frac{3}{2}}}{21} d x} = \frac{2 \sqrt{21} x^{\frac{5}{2}}}{105}$$
加上積分常數：
$$\int{\frac{\sqrt{21} x^{\frac{3}{2}}}{21} d x} = \frac{2 \sqrt{21} x^{\frac{5}{2}}}{105}+C$$
答案
$$$\int \frac{\sqrt{21} \sqrt{x^{3}}}{21}\, dx = \frac{2 \sqrt{21} x^{\frac{5}{2}}}{105} + C$$$A