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 Non linear curve fiting

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T O P I C    R E V I E W
carmenritu Posted - 06/14/2012 : 04:59:18 AM

Hello. I want to adjust a formula that it isn't in Origin function.

.

I defined the fitting function as follows (2 parameters A and B):
y=(1-(x/A))^(-B)
For the initial estimation of the values I used A= 52 and B=3, I think that these values are suitable.
I tried to fit the following values:

I tried to run the non-linear curve fitting but the fitting parameter are unreasonable, there is even no fitting curve on the result graph.
Thanks for any help.
2   L A T E S T    R E P L I E S    (Newest First)
carmenritu Posted - 06/14/2012 : 10:18:57 AM
Thanks to your help! I solved my problem
Sam Fang Posted - 06/14/2012 : 06:25:55 AM
You can choose initial estimation as A=53, B=3. And the fitting will succeed.

Because you choose A=52, and the last point's x is also 52,then (1-x/A)^(-B) for x=52 will be infinite.

Sam
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