I would like to differentiate the function s, and be able to evaluate it for different w afterwards. I tried the following:
s[w_, V1_, V2_, V3_] = -Exp[-(V1 + V2)/2 - V3] + Exp[-(V2 + V1)/2]/(Exp[(V2 - V1)/2] + Exp[-(V2 - V1)/2]) (11 w^2 - ( Exp[-V1] + Exp[-V2] Exp[-V3] + Exp[-V2] + Exp[-V1] Exp[-V3])^2) D[s[w_, V1, V2, V3], w]
This is what I got
(22 E^(1/2 (-V1 - V2)) w_ Pattern^(0,1)[w, _] )/(E^((V1 - V2)/2) + E^( 1/2 (-V1 + V2)))
I don't understand why "pattern" shows up in the expression, and what it might mean. I think I might have done something wrong with the patterns, but why don't I just get some kind of error?