Integral of $$$\frac{\pi x \sin{\left(7 \right)}}{20}$$$

Find $$$\int \frac{\pi x \sin{\left(7 \right)}}{20}\, dx$$$.

Apply the constant multiple rule $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ with $$$c=\frac{\pi \sin{\left(7 \right)}}{20}$$$ and $$$f{\left(x \right)} = x$$$:

$${\color{red}{\int{\frac{\pi x \sin{\left(7 \right)}}{20} d x}}} = {\color{red}{\left(\frac{\pi \sin{\left(7 \right)} \int{x d x}}{20}\right)}}$$

Apply the power rule $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ with $$$n=1$$$:

$$\frac{\pi \sin{\left(7 \right)} {\color{red}{\int{x d x}}}}{20}=\frac{\pi \sin{\left(7 \right)} {\color{red}{\frac{x^{1 + 1}}{1 + 1}}}}{20}=\frac{\pi \sin{\left(7 \right)} {\color{red}{\left(\frac{x^{2}}{2}\right)}}}{20}$$

Therefore,

$$\int{\frac{\pi x \sin{\left(7 \right)}}{20} d x} = \frac{\pi x^{2} \sin{\left(7 \right)}}{40}$$

Add the constant of integration:

$$\int{\frac{\pi x \sin{\left(7 \right)}}{20} d x} = \frac{\pi x^{2} \sin{\left(7 \right)}}{40}+C$$

$$$\int \frac{\pi x \sin{\left(7 \right)}}{20}\, dx = \frac{\pi x^{2} \sin{\left(7 \right)}}{40} + C$$$A