Fundamental Formulae

Under this column, I'm going to display the fundamental formulas from mathematics, physics, chemistry and biology, especially some new formulas derived by myself. This column may be helpful to school students as well as scientific researchers.

As I always declaim to students, if you know the right formula for a particular subject, you do not need to do much practice. Formulas are summarized and proved by our predescents and ancestors., more importantly, formulas provide ideas to solve problems, and also save time for solving problems. 

Every subject in math and science starts from a few axioms or postulates.  It is human's work to derive formulas from the axioms. For example, Euclid developed the classical geometry just from 5 postulates. Einstein's relativity theory was based on 2 postulates. Once knowing all the formulas in a subject, one can see what conclusions have not been drawn yet, so, one can discover something new.

Formulas are for reference, not for memorizing. Of course, as a student, if you can meomerized as many formulas as you can, you will score high in any exam or contest. As a scientific worker, it is better to understand how are the formulas derived. If you can derive something new, you are a scientist or mathematician.