Critical points are points where a function may obtain their minimum or maximum value. They play a critical role (pun intended) in analyzing the increasing and decreasing intervals of functions, and in finding their minimum and maximum points.
Concavity describes the shape of a graph as it increases or decreases: a graph that's concave up is shaped like a cup, U, and a graph that's concave down is shaped like a cap, ∩. Learn more about concavity and how it relates to a function's second derivative.
Solve problems about motion on a 2-dimensional plane using the power of differential calculus. For example, given the (x,y) position of a particle as a function of time (x(t),y(t)), find the particle's position when its acceleration is 0.
Solve geometrical and real-world problems that concern multiple quantities that change at different, but related, rates. For example, given the rate of change of a circle's radius, find the rate of change of the circle's area.
The mean value theorem states that if a function f is continuous on the closed interval [a,b] and differentiable on the open interval (a,b), then there exists a point c in (a,b) such that f'(c) is equal to the function's average rate of change over [a,b].
L'Hôpital's rule provides us with an easy, almost magical way of finding indeterminate limits of quotients of functions using the functions' derivatives. In short, the rule says that if the limits of functions f and g at x=a are 0 (or ထ) and the limit of f'(x)/g'(x) at x=a is equal to L, then the limit of f(x)/g(x) at x=a is also equal to L.