The Natural Base e

The number you may not recognize is e. The number e is the base of natural logarithms and e is approximately equal to 2.71828.This number is irrational and goes on forever without any pattern. You may have the number programmed into your calculator. See how to find the button on your graphing calculator.

Natural logarithms have a base of e, y = log_e. Natural logarithms are written as y = lnx and have the same properties as other logarithms, but the base is the number e.

The following are the graphs of both y = e^x and y = ln(x). The red graph is y = e^x and the black graph is y = ln(x).

y = e^x and 2. y = ln(x)