Recognitions:

## What does "exp" mean?

I have a math expression which has what appears to be a function called exp() and I don't know what it means. It's on this site right here http://www.nasatech.com/Briefs/Jan98/LEW16501.html

Here is the link to the picture of the expression itself.
http://www.nasatech.com/Briefs/Jan98...EW16501_eq.gif

Does anybody know what exp is?

 Recognitions: Gold Member Science Advisor Staff Emeritus "exp" means "exponential" function. In other words, exp(x)= ex. It's used when it is to much trouble or too expensive to Add superscript on top of superscript. The example you give would have a fraction in the exponent. Actually, nowadays, with computerized word processors, it's relatively easy to print complex expressions and you don't see "exp" as much. Lets see if it works in "tex": $$r= D[e^{\frac{-1}{RT}\frac{\partial G}{\partial X}}-1]$$ I wrote this originally, assuming that the question was only that "exp" seemed unusual. ex is, simply, the number e (about 2.18) to the x power. It is the inverse function to natural logarithm.
 means experience :p