Clearly, the standard definition $D_{v}(f):= \nabla f\cdot v$ tells us nothing when $\nabla f = 0$. In such a case, what other generally applicable methods tell us whether the function increases, decreases, or is level in a direction?
2026-04-13 16:02:03.1776096123
Can we define a “directional derivative” at saddle points?
302 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in MULTIVARIABLE-CALCULUS
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