If $y=f(x)$, in the interval $[a,b]$ is rotated about the $x$-axis, the Volume of the solid of revolution is $(fâ(x)=dy/dx)$
- $\int_{a}^{b} \pi [f(x)]^{2} dx \\$
- $\int_{a}^{b}[f(x)]^{3} dx \\$
- $\int_{a}^{b} \pi [{f}'(x)]^{2} dx \\$
- $\int_{a}^{b} \pi^{2} f(x)dx \\$