On Thu, 18 Nov 2010 13:43:51 -0500, Stavros Macrakis <macrakis at alum.mit.edu> wrote: > (%i65) ex: A * exp(-b * exp(-k * x)) = y $ > (%i66) solve(ex,x); > (%o66) [x = log(b/log(A/y))/k] Neat, so the expression needs to be an actual equation, not a function. Thanks! -- Seb