Euler's Equation

var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));This is the month of Leonhard Euler's birth; Euler was one of the most prolific, productive mathematicians of all time. His so-called "Euler's Equation" or "Euler's Identity" is