Nope, the concept of directional derivatives extends easily to non-unit directions, and it's pretty nice.
evelynk
If u is not a unit vector, what is the relationship of the directional derivative of the nonunit vector to the unit vector version? What are nonunit vector directional derivatives used for?
Does u has to be a unit vector?
Nope, the concept of directional derivatives extends easily to non-unit directions, and it's pretty nice.
If u is not a unit vector, what is the relationship of the directional derivative of the nonunit vector to the unit vector version? What are nonunit vector directional derivatives used for?