Complex polynomial of an aggregating system

[sadrian]

Hopefully this is in the right spot. First off I am fairly new to MathCad.

I am having a problem with getting the calculated values from a complex polynomial equation to fit my data. I am working with an aggregating protein system. I know the total concentration of protein subunits and the ratio of monomer to total at a variety of concentrations. This ratio has to be between 0 and 1. I am trying to fit an equilibrium equation to this data. I have solved the polynomial equation to equal 0 and have put in guesses for the variables and input a matrix of experimental total concentrations.

I would like it to give me all of the values of alpha between 0 and 1 at each total concentration because that is the physiologically relevant root. I also need to check the variance from the experimental values. I do not understand how to get the program to calculate these things.

I have attached the MathCad document here.

Thank you for any help,

Seth

[RichardJ]

Sorry, your Mathcad file is in version 3.1 format, which I can't read. Post a pdf, and maybe I can give an answer based on that.

[VladimirN]

Richard,

In an attachment you can view the contents of Mathcad Prime worksheet.

[LucMeekes · Accepted solution]

Made some modifications. You now get solutions (vary the lower definition of i into any value from 0 to 10), though I can't tell if the results are any meaningful.

Success!
Luc

[sadrian]

Thanks for the help. I used the root function for each i value to obtain an answer. Finding the right parameters was a bit difficult but I got the best fits for the data that was possible. Thanks again for the help.