# Revision history [back]

Hi Volker,

if you take the model

model=a*sqrt(1-b*x^2)


and as an initial guess (1,0.00025) (a good guess made by interact) I get

[a == 1.0000027991978133, b == 0.00024550730310659858]


and if you compare this function with the data provided it looks very good (since I do not know how to post pictures I cannot show you my plot).

Concerning the points around x=1: I have deleted some points from the list near the end and the problem vanishes (I can switch a and b or make some other guesses and the above mentioned solution will be calculated).