This applet illustrates the concept of partial derivative. [br][br][list=1][*]Check the box "y constant" to plot the plane that passes through the point with [math]y[/math] constant, and observe the curve that results from the intersection of the plane and the surface. [br]The partial derivative of [math]f\left(x,y\right)[/math] with respecto to [math]x[/math] measures the instantaneous rate of change of [math]f[/math] when [math]x[/math] changes but [math]y[/math] keeps constant. [br]Geometrically is the slope of the tangent line to the curve that results from the intersection of the plane and the surface. [/*][*]Check the box "x constant" to plot the plane that passes through the point with [math]x[/math] constant, and observe the curve that results from the intersection of the plane and the surface. [br]The partial derivative of [math]f\left(x,y\right)[/math] with respecto to [math]y[/math] measures the instantaneous rate of change of [math]f[/math] when [math]y[/math] changes but [math]x[/math] keeps constant. [br]Geometrically is the slope of the tangent line to the curve that results from the intersection of the plane and the surface. [/*][*]Move the x and y sliders to change the point and observe how the partial derviatives change. [/*][/list]Enter a new function and repeat the previous steps.

Get more information about the partial derivatives at [url=http://aprendeconalf.es/calculus/manual/derivatives-n-variables.html#Partialderivativenotion]http://aprendeconalf.es[/url].