Well, a rational decimal is like a simple 3.1 or 4.5. It just cuts off easily. Another example would be a repeating decimal like 3.333333...
An irrational decimal is like 3.1415682983523576294875 with no pattern or cutoff point.
Sorry if I am wrong.

has gradient

which at the point (-1, 4, 3) has a value of

I'm not sure what the given direction vector is supposed to be, but my best guess is that it's intended to say
, in which case we have

Then the derivative of
at (-1, 4, 3) in the direction of
is

Answer:
Domain= x∉Real numbers
Step-by-step explanation: