Implicit differentiation is a technique used to compute a derivative when a function y = f(x) is given indirectly by an equation that relates x and y. For example suppose that you are given:

x^2 ~+ ~y^2 ~=~16

The equation must be solved for y to obtain an explicit solution, and in this case there are two solutions. The procedure called implicit differentiation works by differentiating both sides of the equation and then solving for dy/dx, so an explicit expression of the derivative is not given. In the video some examples illustrate this procedure.