Critical Points - Math24
https://www.math24.net/critical-pointsClassification of Critical Points Figure 1. Examples of Critical Points. A critical point \(x = c\) is a local minimum if the function changes from decreasing to increasing at that point. The function \(f\left( x \right) = x + {e^{ - x}}\) has a critical point (local minimum) at \(c = 0.\) The derivative is zero at this point.