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Topic: A basic question
Replies: 2   Last Post: Jan 16, 2013 1:27 PM

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Posts: 2,359
Registered: 12/6/04
Re: A basic question
Posted: Jan 16, 2013 11:32 AM
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"Jerry " <> wrote in message <kd6iq9$mmv$>...
> Hello,
> I used this model [y = D+(A-D)/(1+(x/C)^B)] and predicted all parameters using a vector of 'x' and 'y'. For a specific value of 'y', I would like to calculate a value for the 'x' using this model [x =((((D+(A-D))/y)-1)^1/B)*C] derived from the original model. But the calculated 'x' is not what it should be. I am assuming there is something wrong with this model [x =((((D+(A-D))/y)-1)^1/B)*C]. May someone give me a comment?
> Thanks,
> Jerry

Based on what little information provided
(I assume A,B,C, & D are scalars), I suggest two things:

1. Put parentheses around 1/B, i.e.

x =((((D+(A-D))/y)-1)^(1/B))*C

2. Try using element-by-element operators:

x =((((D+(A-D))./y)-1).^(1/B))*C

See if those help.

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