Either the question is boringly trivial and uninteresting, or else you, or someone else, made a mistake copying it: is a constant vector and any function's derivative wrt to a constant is zero, even if you meant to derivate wrt a vector (what is that?) and not wrt some variable.

Perhaps you, or someone else, wanted to check what some partial second derivative wrt the constant vector is, for example or something like this. Who knows...

Tonio