Abstract: The mathematical model is the use of mathematical language to describe the behaviour of a system. Mathematical models are used in particularly in the sciences such as biology, electrical ...

Once a century, a very special day comes along. That day is today — 9/16/25. Pi Day (3/14) often comes with sweet treats; Square Root Day (4/4/16 or 5/5/25, for example) has a certain numerical rhyme.