Bibliography.

J. D. Logan, “Applied Mathematics” or “Εφαρμοσμένα Μαθηματικά”.

Parameters and variables

A system is described via variables. Examples are

• Positions of particles.
• Populations of a biological species.
• Cost of production and earnings.
• ...

Also, we identify the parameters which may have an effect on the system and on the processes that will be described.

See Malthus Model. Add immigration and emigration.

A chemical reaction

The reactants are transformed into products.

$$ A \longrightarrow \text{products}. $$

A chemical reactor with volume $V$.