12.10: Common Mistakes and Best Practices

Topic

Common Mistake

Better Practice

Polynomial vectors

Forgetting zeros for missing powers

Include every coefficient from highest degree to constant term

Interpolation

Using interpolation outside the data range without thinking

Recognize that this becomes extrapolation and may be unreliable

Curve fitting

Choosing the highest polynomial degree automatically

Choose a model that is simple and physically reasonable

polyfit/polyval

Finding coefficients but forgetting to evaluate them

Use polyfit to fit, then polyval to predict or plot

Anonymous functions

Using ^, *, / when arrays are expected

Use .^, .*, ./ for element-by-element operations

trapz

Using too few points

Use enough points to approximate the curve well

fzero

Expecting it to find all roots

Use multiple guesses or intervals for multiple roots