E in math is an irrational number that means it cannot be written as a ratio of A over B. Solve equations with E with help from a professional private tutor in this free video clip.

### Transcript

Hi, I'm Rachel, and today we're going to be going over how to solve equations with E. E in math is an irrational number that means it cannot be written as a ratio of A over B, it goes on forever and it's approximately 2.718...it goes on forever. So when you are solving the equation with E you can either keep E as E written out like that as the variable just like you write Pi as Pi, sometimes in equations or you can approximate it with 2.718. You can also use the button E on your calculator, there is an E button if you have a good graphing calculator and so you can actually just press the E button and we're doing something like 5 times E you can just multiply it and if you don't have your calculator you can just usually use this approximation and multiply 5 times 2.718. When do we use E? We use E in natural logs right, so that's, we write that as Ln. We also use E in something like continuous compounding, E to the R minus 1 is an example of a continuous compounding and in this case R is the rate. So if for example, we knew that the rate was 8%, right, then we know that that's E times .08 minus 1 and you can solve from there, right, either approximating it as 2.718 or as using the E button on your calculator. And that's an example of using E in an equation. I'm Rachel and thank you for learning with me today.