Gradients in 2D and 3D
Gradients in 2D and 3D
For a smooth surface in 3D, representing a function , the gradient at a point on is a vector in the direction of maximum change of . Also shown is the corresponding contour plot, which is the projection of onto the - plane. The red arrows on the surface and contour plots show the magnitude and direction of the gradient.
S
z=f(x,y)
(,)
x
0
y
0
S
f(x,y)
S
x
y
The dot shows the point at which the gradient is computed. You can vary the point by dragging the locator.
(,)
x
0
y
0
Change the function with the pull-down menu.
Rotate the graph to convince yourself that the gradient is normal to the surface at the point.