. 1- (. 1, ), 2- 2 = 1 (. 1,).
21 2 = 1 2- Δ21, 1- :
Δ21 = 2Δ21 = 1 Δ21 = Δ21.
21 ,
Δ21 = 21 = S + S + S -
M2, N2 Q2 , .
1-
()
) 2-
()
. 1
, , . o . (, - ), , ; . - , ( ), .
( ) , , , ( ). , , , N, Q, , , , Np Q.
1 2 , ( k), :
Δmn = 21 = S + S + S ,
Δmn m =1, n ( n).
, , :
Δmn = S + S dx + S .
( ).
òMmMndx[1]. , m n, . , , m, ; , .
m = xtg α;
α . 2.
ò MmMndx,
Mn dx = tg α n dx = tg α Ωn,
|
|
n dx = dΩn Ωn n.
Ωn Ωn n 00′.
:
Ωn = Ωn×,
Ωn n.
Mn dx = tg α× Ωn.
tg α = ,
Mn dx = Ωn .
. 2
. 3
, ( ) , . , , , , , . 1925 . . . , , , .
, EJ. , EJ.
, . , . , Mi Mk (. 3, ), , Ωi k( Ωi Mi k k) Ωi k ( Ωk Mk i Mi).
, :
Δ = S .
, . , .
:
Δ = S ,
.
Δ = S l , - ().
[1] òNmNndx òQmQndx.