Euler

One of the great geniuses ever lived is Leonhard Euler. He contributed to number theory, topology, calculus, infinite series and many branches of the mathematics in 18th century. He started his education in Basel and worked in St. Petersburg and Berlin for most of his life.

Some of the discoveries by Euler

• e^ix = cos(x) + i sin(x) and e^i(pi) + 1 = 0
• v - e + f = 2 to describe relation between verities, edges and faces of polyhydra. 
• Euler line on which orthocenter, circumcenter and centroid are collinear for any triangle.
• Euler totient function to count the numbers that are relatively prime to a number
• Summation of series like ∑ (1/n²) , ∑ (¹/n_!), ...

Leonhard Euler

Euler's identity 

Euler's characteristic

Euler's formula

Euler's totient function

Euler's line 

Euler's biography