H - gradient of a scalar function

PX153 - H1 - directional derivative and gradient vector of scalar functions
PX153 - H2 - visualising variability of a scalar function - contours
PX153 - H3 - gradients of functions of three variables
PX153 - H4 - application of gradient in physics - the potential of a conservative force
PX153 - H5 - coordinate systems revisited
PX153 - H6 - gradient operator