One-sided directional derivative in all directions, but no
Chapter , Problem 98PE(choose chapter or problem)
One-sided directional derivative in all directions, but no gradient The one-sided directional derivative of ƒ at P (x0,y0,z0) in the direction is the number Show that the one-sided directional derivative of at the origin equals 1 in any direction but that ƒ has no gradient vector at the origin.
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