[SOLVED] minimum and maximum values An object with weight W is dragged along a horizontal plane by a force acting along a rope attached to the object. If the rope makes an angle [tex]\vartheta[/tex] with the plane, then the magnitude of the force is F= Z(W)/Z sin [tex]\vartheta[/tex] + cos [tex]\vartheta[/tex] Where Z is a positive constant called the coeffecient of friction where 0< Z<[tex]\pi[/tex]/2. Show that F is minimized when tan [tex]\vartheta[/tex] =Z The theorem's I am allowed to use: The extreme value theorem Fermat's theorem I don't really understand what the problem is asking me. What do they mean by F is minimized? Maybe if I knew that I could do it.