"e" day

We celebrate "e" day, on 7th February (since e = 2.718281828459...). The number "e" is very special in math, in a similar way that "pi" is special.

One of the most amazing equations involving e is Euler's Formula:

e^ix = cos x + i sin x, where i = √(−1)

This formula makes the connection between the exponential function, trigonometry and the imaginary unit.

In the special case when x = π, we get

e^iπ + 1 = 0

This profound formula connects the numbers e, i, π, 1 and 0, with the fundamental operations plus (+) and equals (=).