Example 6-3-2. Warning Example - Diagonals matter
Channel: Business Calculus with Excel
Date: 2021-07-17

Example 6-3-2. from Business Calculus with Excel.
https://mathstat.slu.edu/~may/ExcelCalculus/sec-6-3-CriticalPointsExtrema.html
Seeing the a minimum in both x and y directions does not mean it has to be a minimum