i saw your worksheet , but i cant get any solution !! i use maple 15 .

thank you

dear Markiyan Hirnyk , what can i do to be a solid person ? do you mean 'escorpsy' ?

however in  https://controls.engin.umich.edu/wiki/index.php/Recorded_Lectures , you download lecture 16 .

thank you Preben Alsholm ,   new.mw , buw how the last command to show critical points didnt work .