Electric potential along the x-axis

1. Nov 30, 2013

chicagobears34

1. The problem statement, all variables and given/known data
The electric potential along the x-axis is V=100e^(−2x/m), where x is in meters.
Find Ex at x=1.0m and Ex at x=2.1m

2. Relevant equations
V=Ed
Ex = dV/dx (?)

3. The attempt at a solution
I took the derivative of V and got (-200/m)e^(-2x/m)
I don't know what m is and I'm just not sure how I can get an integer value for Ex at x=1.0m and 2.1m
EDIT===
I assumed m=1 and got the correct answer, don't understand what m is though

2. Nov 30, 2013

TSny

m might just represent units of meter. So the 2 in the exponential has units of 1/m and they decided to show that explicitly.