Polymath program nonlinear regression

In nonlinear regression analysis, we search for those parameter t alues that minimize the sum of the squares of the differences beiw een the measured values and the calculated values for all the data points.- Not only can nonlinear regression find the best estimates of parameter values, it can al,so be used to discriminate between different rate law models, such as the Langmutr-Hin-shelw ood models discussed in Chapter 10. Many software programs are available to find these parameter values so that all one has to do is enter the data, The Polymath software will be used to illustrate this technique. In order to carry out the search efficiently, in some cases one has to enter initial estimates of the parameter -alues close to the actual values. These estimates can be obtained using Ihe linear-least-squares technique discussed on the CD-ROM Professional Reference Shelf. 

A plot of the reciprocal reaction rate versus the reciprocal urea concentration should be a straight line with an intercept 1/rmax and slope M/ max (Lineweaver-Burk plot). We can solve this equation either graphically or numerically using the POLYMATH nonlinear regression program. The following table can be set up ... 

With the POLYMATH nonlinear regression program the rate law with the parameter k and n can be determined. 

These topics are explained in specialist books and briefly by CHAPRA CANALE. Polynomial and multilinear regression programs are in POLYMATH and AXUM, nonlinear in CONSTANTINIDES and AXUM. No periodic data are regressed in the present collection. 

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