a non linear model combining an exponential and a linear fit is applied to the data using nls. starting values are calculated based on the data. Constraints are applied to the model based on the known constraints of the aimed model.
ApplyCombMod2(data, y = "y", x = "x")
data frame containg x and y data to which combined exponentail and linear model is ought to be applied to
name of column in data containing y data
name of column in data containing x data
model parameters