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Faculty of Applied Engineering and Urban Planning. Civil Engineering Department. Numerical Analysis. Curve Fitting. Lecture 13 Week 11. 2 nd Semester 2007/2008. From Dr. Arafa Lecture Notes. From Dr. Arafa Lecture Notes. From Dr. Arafa Lecture Notes. Interpolation VS. Curve Fitting.
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Faculty of Applied Engineering and Urban Planning Civil Engineering Department Numerical Analysis Curve Fitting Lecture 13 Week 11 2nd Semester 2007/2008
Definition • Interpolation is the process of finding equations to approximate straight lines and curves that best fit given sets of data. • Curve Fitting is the process of finding the dependent variable from some data of the independent variable . Regression can be linear (straight line) or curved (quadratic, cubic, etc.)
Straight Line Fit: A Polynomial Function of First Degree If there is some theoretical basis on which we believe the relationship between the two variables to be: we should set up the following system of equations from the collection of many experimental data:
Straight Line Fit: A Polynomial Function of First Degree This system can be written as: And solved using the following formula:
Straight Line Fit: A Polynomial Function of First Degree Solving the previous system leads to the following equation:
Linearization Consider the following equation: