Reference:
VECTOR ANALYSIS: Schaum’s
Outlines Series
by Murray Spiegel , Seymour Lipschutz
, Gradient of a Scalar Field
For a scalar function W of three variable W(x,y,z), the gradient of W is
a vector quantity given by:
- The gradient points in the
direction of the greatest rate
of change (increase/decrease)
of the function.
- and its magnitude is the slope
(rate of change) of the graph
in that direction.