Tutorial 15: control theory, part I

Control theory is the branch of engineering that tries to answer questions like "given a system configured in a particular fashion, will the system behave reasonably?" That is, control theory deals with analyzing systems. Control theory also tries to answer the question "given a system with (negative) feedback, what can I add to my system to see to it that my system will meet its specifications?" That is, control theory deals with designing systems, too.