TME 310 - Computational Physical Modeling

Root-finding

Lorne Arnold, PhD, PE

University of Washington Tacoma

Roots of equations

A root of an equation is a value of the independent variable that makes the equation equal to zero.

For example, the root of a linear equation with the form

\[ y = mx + b\]

is

\[-\frac{b}{m}\]

Non-trivial root-finding

What about more complicated examples?

We have a few options:

  1. Graphical methods
  2. Bracketed methods
  3. Open methods

Graphical methods

A brute force solution:

  • Plot the function
  • Look for where it equals zero

Graphical method

Pros and cons (graphical methods)

Pros

  • Reliable

Cons

  • Slow
  • Imprecise

Graphical methods are a great check for faster, automated methods.