Born's conditions for an acceptable "well-behaved" wavefunction F(x): 1. it must be finite everywhere, i.e. converge to 0 as x -> infinity 2. it must be single-valued 3. it must be a continuous function 4. and dF/dx must be continuous. I'm having difficulty understanding the last condition for a specific example. I have a wavefunction, F(x) = exp[-|x|], and the derivative at x = 0 does not exist. Is dF/dx still continous at x=0?