1. The problem statement, all variables and given/known data I was following a derivation of some laws and I didn't get how they approximate some portion of the expression. That portion/part is exp[gbH/(2kT)]. The book says gbH/2 <<1 and therefore exp[gbH/(2kT)] = 1+gbH/(2kT). 2. Relevant equations 3. The attempt at a solution I agree with the value 1, but where did gbH/(2kT) come from? Please help. My understanding is that if gbH/2 is way less than 1, then e.g exp[1.0*10^-15/KT)] = 1.