::::::The rate of decline need not be constant, and nothing in the counterexample implies that it would be. But it's continuous and differentiable -- surely not a step function.--[[User:Aschlafly|Andy Schlafly]] 00:06, 17 June 2011 (EDT) | ::::::The rate of decline need not be constant, and nothing in the counterexample implies that it would be. But it's continuous and differentiable -- surely not a step function.--[[User:Aschlafly|Andy Schlafly]] 00:06, 17 June 2011 (EDT) |