Hello, thank you for your time.

I am trying to graph the following function:

f[x_] := 1/(Exp[(x-u)/(k*T)]+1);

Plot[f[x_],{x,0,1}]

I tried doing the above while setting T=0, but quickly learned that wouldn't work. So I tried the following:

f[x_] := 1/(Limit[Exp[(x-u)/(k*T)],T->0]+1);

Then I tried to use the same plot. This gave me no errors but now unfortunately nothing is showing up on my graph. It should look like a step-function, where f(x) = 1 until x=u, then at that point f(x)=0 the rest of the way.

Any help is appreciated, thank you!