Who are the great mathematician and their formula?

Answer 1

There are many great mathematicians who have formulas named after them.

I'll start with Leonhard Euler (1707 - 1783), and Euler's Formula:

• eix = cos(x) + i sin(x), where x is expressed in radians, and i is the imaginary unit i=sqrt(-1)

Gabriel Cramer, and Cramer's rule (not really a formula though). It is a method for solving systems of linear equations by expressing the equations as a matrix of coefficients, then taking determinants.