GRADIENT

Purpose:

Calculates the 2D derivative of an array.

GRADIENT(a)

An array.

An array.

(x, y) = fxyvals(-2, 2, .1, -2, 2, .1);

z = cos(x*y);

g = gradient(z);

calculates the surface derivative of cos(x*y).

W1: plot3d(g)

W2: plot3d(z);shadewith(W1);

shades the original surface with its gradient.

If the input is a series, the derivative is returned.