Please check my steps for global extrema of functions. 1) Finding Critical points. 2) Finding values of f at critical points and end-points. 3) Checking which one is largest and which is smallest. 4) Largest would be Global maxima and the smallest would be minima. Now a question, i know how to find global extrema if they are at end-points. How can i find local extrema if they occur at end-points? I will be thankful to you if you illustrate it with a simple example.