1 x2 + y2 + z2
n
lim x - IA(x, y, z) l3(dxdydz),
n"
3 1 + x2 + y2 + z2
R3
A = {(x, y, z); x > 0; y > 0; z > 0; x2 + y2 + z2 < 2}.


2x2 - y
lim n sin l2(dxdy),
n"
n
A
A (0, 0), (0, 1), (4, 0).

1
lim (n - 3 ln z - ln(x2 + y2))n(x2 + y2)3/2 l3(dxdydz),
n"
nn
U
U = {(x, y, z); 1 d" x2 + y2 d" 9, 1 d" z d" 2}.



xyz x2 z2
lim 1 - exp + l3(dxdydz),
n"
n3 2 3
U
x2 z2
U = {(x, y, z); + d" 1; 0 d" y d" 3}.
2 3

(1 + x + y)n 2
lim e-x-y-z /2 l3(dxdydz).
n"
1 + (1 + x + y)n
(0,")3



x2 + y2 z
lim n2 sin cos l3(dxdydz),
n"
n2 n
U
U = {(x, y, z); x2 + y2 d" 4, 0 d" z d" 2}.