Question

Просьба помочь.....................

Answer 1

$z=x^3-3y; ,; ; M(a,b)\\z'_{x}=3x^2; ,; ; z'_{y}=-3\\(z'_{x})|_{M}=3a^2; ,; ; (z'_{M})|_{M}=-3\\z''_{xx}=(z'_{x})'_{x}=6x; ,; ; z''_{xy}=(z'_{x})'_{y}=0; ,; ; z''_{yy}=(z'_{y})'_{y}=0$

$overline{gradz}|_{M}=(z'_{x})|_{M}cdot overline {i}+(z'_{y})|_{M}cdot overline {j}=3a^2cdot overline {i}-3cdot overline {j}\\overline {gradz}|_{M}=(3a^2;-3)$