When is E-day?
Tuesday February 7thEvery year on February 7th, E-Day commemorates the mathematical constant e, also known as Euler's Number. It's also a day to learn more about Leonhard Euler, the Swiss mathematician.
![E-Day - February 7](https://fabcdn.com/images/jpg/30deg_out1/157.2023-february-7-e-day.jpg)
You may recall seeing a little "e" in any advanced math or physics course. Though it's a letter, Euler's number is actually called Euler's number. It has a mathematic value of 2.718281818. The digits go on forever in a series that never repeats, like pi.
Euler's number is usually used when trying to solve a formula or equation. Trying to figure out the rate of change is one example of how Euler's number is used. Euler's number helps determine the rate of exponential growth or decay in biology. Population estimates are another example where Euler's number is commonly used.
Euler's number can also help figure out how compound interest drives wealth to increase. This is exactly how mathematician Jacob Bernoulli was using this number. Bernoulli, a 1638 entrepreneur, was trying to figure out how much money would rise if it were compounded more than once a year.
Leonhard Euler, who was born in 1748, began to work with this mathematical constant. Euler was the first one to show that it was an irrational number. He used the letter "e" for the word "exponents" when dealing with the constant. However, the letter was still commonly associated with his name. Euler is also known for establishing the study of graph theory and topology. He is regarded as one of the best mathematicians in history.