Suppose that a substance is dissolving into a liquid which is at rest in a container. assume further that no mass enters or escapes the container. on the basis of (4-2) with u = 0, give a physical argument showing that lim c(x, t) = co, 14시 where co is a constant. argue that co c(x, 0) dx, where v is the set making up the container and |v is its volume.