22. , . .
).
: , . , .
.
DÌ R 2 .
D n D i, D i DS i,
l n = .
D i ÎD i f (Pi). D. {s n } , , l n 0 n ¥ ( ).
22. 1.
{s n } ln 0, D, , D f (, ) .
, :
D.
4.1.
f (P) D, ( ).
:
1.
2. -
3. ,
( )
4. " P (x, y)ÎD, .
5. m £ f ((x, y) £ M, " P (x, y)ÎD, .
6. Q (x, y)Î D: = f(Q) ×|D| ( .)
(4-6 ).
: ( R 3) , z= 0, , D Î R 3, OZ.
D D ij , f (ξi, ηj), (ξi, ηj) , Dij .
V. . ,
V. . = .
, , , . ( ) .
D , D , . D . [ a, b ] [ c, d ] OY .
:
a < x 1 < x 2 <... < xn = b
c < y 1 < y 2 <... < yk = d
D (, ) Dij, i= , j = , :
| Dij | = D Sij = D xi D yj, D xi = xi- xi- 1,D yj = yj - yj- 1
, :
,
(ξi, ηj) - , Dij.
|
|
,
, ( ) .
22.2.
D Î R2 OY, x = a, x = b, y = j1(x), y = j2(x), j1(x) £ j2(x) x Î[ a,b ].
, OY PÎD, 1, 2. 1 ( OY), 2 . y = j1(x), - , y= j2(x) .
, , .
, , , :
, : y = c, y = d, = y1(), = y2 (), y1() £ y2() y Î[ c,d ].
22.2.
f (x,y) D .
1) D OY,
2) D OX,
, , ( ). , . , . () , , .
( ) , , . : no dx - no dy; no dy - no dx ( ).
1.
D .
2.
( : + = 2, = 1, y = 1)
=