I'm really having trouble trying to figure out a function.
So, the surface area $S$ of a sphere is a function of its radius $r$ given by $S(r) = 4\pi r^2$. I'm trying to find $S(2)$ and $S(3)$.
Am I supposed to plug in $2$ and $3$ respectively for $r$? Silly question perhaps, but I'm confused. :(