$$$4 t \sin{\left(c^{2} \right)}$$$ の $$$t$$$ に関する積分

$$$\int 4 t \sin{\left(c^{2} \right)}\, dt$$$ を求めよ。

定数倍の法則 $$$\int c f{\left(t \right)}\, dt = c \int f{\left(t \right)}\, dt$$$ を、$$$c=4 \sin{\left(c^{2} \right)}$$$ と $$$f{\left(t \right)} = t$$$ に対して適用する:

$${\color{red}{\int{4 t \sin{\left(c^{2} \right)} d t}}} = {\color{red}{\left(4 \sin{\left(c^{2} \right)} \int{t d t}\right)}}$$

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

$$4 \sin{\left(c^{2} \right)} {\color{red}{\int{t d t}}}=4 \sin{\left(c^{2} \right)} {\color{red}{\frac{t^{1 + 1}}{1 + 1}}}=4 \sin{\left(c^{2} \right)} {\color{red}{\left(\frac{t^{2}}{2}\right)}}$$

したがって、

$$\int{4 t \sin{\left(c^{2} \right)} d t} = 2 t^{2} \sin{\left(c^{2} \right)}$$

積分定数を加える:

$$\int{4 t \sin{\left(c^{2} \right)} d t} = 2 t^{2} \sin{\left(c^{2} \right)}+C$$

$$$\int 4 t \sin{\left(c^{2} \right)}\, dt = 2 t^{2} \sin{\left(c^{2} \right)} + C$$$A