This tool is essentialy a brute force search tool, it works by subdividing the domain into a 1000 equally spaced points, and testing each point against the solution criteria.

Data Tables are used to evaluate the function at 1000 points. This is done in columns X and Y. The searching is done in columns Z and AA. Note the use of Conditional Formatting in showing or hiding cells (for example, contents of cells A9 and B9 seem hidden until B8 is set to 'Target'.) The use of Conditional Formatting makes the tool appear sophisticated. No macros are used in this tool. See the related tip: Macro Overdose.

Also note that like many tools employing numerical methods, this tool is not perfect. Numerical methods have limitations and these must be kept in mind while using them or while interpreting the results obtained from them. Read this wiki page on numerical methods for an overview.