exp is the function that comprises of Euler's number e raised to a particular number's power. The Exponent function is a particular power series, that is based around a rather classical explanation of The sum of all x to the power of k divided by k factorial such that it is equal to 1 + x + x^2/2 + x^3/6 + x^4/24 + ... and so on to infinity.
if you need a visual.
Also your program needs some help, exp(2.71828) is just e^e, which is a constant and wont do anything for that formula.
you need something like exp(points/..land..etc)
consult the game wiki if you need the formula, it's in pretty easy to read Wiki language for anyone who cares to look.