O'Reilly logo

Good Math by Mark C. Chu-Carroll

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

The Number That’s Everywhere

What is e?

e is a transcendental irrational number. It is roughly 2.718281828459045. It’s also the base of the natural logarithm. That means that by definition, if ln(x) = y, then ey = x.

Given my highly warped sense of humor and my love of bad puns (especially bad geek puns), I like to call e the unnatural natural number. It’s natural in the sense that it’s the base of the natural logarithm; but it’s not a natural number according to the usual definition of natural numbers. (Hey, I warned you that it was going to be a bad geek pun!)

But that’s not a sufficient answer. We call it the natural logarithm. Why is a bizarre irrational number that’s just a bit smaller than 2 ¾ considered natural?

The answer becomes ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required