2. 71828.... is an irrational number that appears in several Euler's number, e= branches of math, especially calculus. It's just a constant similar to . Since any exponential function can be written with any base, e is often used as a default base. For example, Excel could have written the equation for this data as y = 22, but 0.6931x defaulted to y = e 17 Y 0 1 15 14 1 2 13 y = 0.6931x -12- 234 4 11 10 9 B 4 16 -7 6 4 4 2 3 4 Convert y=10% to base. e.