Prerequisite concepts Differential Calculus Difference / Change Understanding both difference (how far apart two values are at one time) and change (how far apart the value of a single parameter is at two different times) is necessary for understanding derivatives. New prereq concept The Valley New taught by The gradient can tell you a small change in a function in any direction (differentials edition) $df=\vec \nabla f \cdot d \vec r$ Representations used No activity! NEEDS NAME $\vec \nabla f$ ENTER LONG DESCRIPTION No activity! NEEDS NAME $d \vec r$ ENTER LONG DESCRIPTION New representation New needed for concept