> "It is unworthy of excellent persons to lose hours like slaves in the > labor of calculation."
> . . . Gottfried Wilhelm von Leibniz
What did Leibniz mean by "labor"? I think he meant that using Calculus one could save considerable time in solving various problems. For instance, optimising problems, related rate problems, approximating roots, etc. Which means you trade much labor for the minor work of taking a derivative and solving an equation.
Nowadays, of course, taking derivatives is considered labor.