N
j N0
N N0 . NN0. , N0, , NN0 , NN0.
. N0 , N0 .
, , .
z = f(x, y), f(x, y) , 0(0, 0), N0(x0,y0,(x0,y0)) :
.
:
f(x, y) (0, 0) ( z) (0, 0) (0+D, 0+D).
, .
.
(1, 1, 1).
:
:
f(x, y) (, ). :
:
. , x = 1, y = 2, z = 1.
Dx = 1,04 1 = 0,04, Dy = 1,99 2 = -0,01,
Dz = 1,02 1 = 0,02.
u(x, y, z) =
:
u :
: 1,049275225687319176.
f(x, y) D, .
.
.
, .
. .. .