One strategy for earning income with derivatives is selling (or "writing") options to collect premium amounts. Options often expire worthless, allowing the option seller to keep the entire premium ...

A lawyer shall act with reasonable diligence and promptness in representing a client.

Analytical definition of continuity, limits of functions and derivatives in terms of a limit of a function. Properties of continuous and differentiable functions. L'Hopital's rule, Rolle's theorem, ...