# Happy PI Day!

Blog Post created by Ahmad Fattahi on Mar 14, 2011

Today is March 14 or 3/14, hence PI day! Happy PI day to all PI Community including our beloved OSIsoft vCampus.

thinking about PI, I couldn't resist revisiting this beautiful equation, known as the Euler's formula. The equation is:

e ^ ( i * pi) + 1 = 0

You may ask "Where is the beauty?" Well:

• e is the base of the Natural Logarithm whose roots go back to the integral of the function y = 1 / x.
• i is the imaginary unit; as you know i = sqrt (-1).
• pi is the irrational number which is the ratio of every circle's perimeter to its diameter.
• 1 is the multiplicative identity hence pretty fundamental in calculus.
• 0 is the additive identity hence pretty fundamental in calculus.

As you see all these numbers come from very different backgrounds and is each very fundamental in its own turn. The Euler's equation bonds all of them together in a very basic way.

Some geeks call this "the most beautiful equation in mathematics"!