Answer to Question #328191 in Analytic Geometry for Dudu

Question

Let F be the R²-R function defined by f(x,y)=(x-y)³.

1.determine the rate of increase in f at the point (2,1) in the direction of the vector(1,-1).then use theorem.

2.what is the rate of increase in f at (2,1) in the direction of the negative x-axis?

3.determine the maximum rate of increase in f at (2,1). In which direction is the maximum rate of increase? (read corollaries).