What does exp mean in the P(f) equation?

[fusi0n]

I was given an equation:

P(f)=(sqrt(2/(Pi*N)))*(exp(-(nf^2)/2))

What math exercise is exp referring to? Thanks a lot for any help.

 

[Galileo]

It's the exponential function.
$$e^x=\exp x$$

 

[fusi0n]

should've known that... thanks