1. Terry A. Ring ChEN 4903 University of Utah
Homework I Discussion
Terry A. Ring
ChEN 4903
University of Utah

2. What was I to learn from this HW?
Learn how to do a non-linear least squares.

3. Comparison of Linearized and Non-linear Least Squares
Linearized Fit Arrhenius Expression
Non-linear Fit
Which is best?

4. What was I to learn from this HW?
Learn how to combine Non-Linear least squares with error propagation.
Do Error propagation using two methods
Partial derivatives
G=f(y1,y2,y3,…)
Excel Method
fi = f(x1,x2,...,xi+si,...,xn)

5. Non-linear Fit
Fit Results a

6. Error Propagation Partial Derivatives
Given D=0.010±0.001 m, V= 1.0±0.2 m/s, T= 358.0±2.5 K
Error (σ) in Nu
[(1.198* σV)2+(0.599* σD)2+(4.872* σT)2]1/2
Since dNu/dT is the largest piece of the error
It is the variable that must be better controlled
to lower the total error

7. Error Results