This program displays the graph z = f(x,y) along with cross-sectional curves obtained by fixing one variable and the tangent lines to these curves. The slopes of these tangent lines are the partial derivatives f_x and f_y. The visualization makes concrete the idea that partial differentiation measures the rate of change of a multivariable function in one coordinate direction while holding the others fixed.
Controls: Click and drag to orbit, scroll to zoom.
