D,
- . I III.
, -, , -, a.
, "" U0 . , , "" , . .
, , - "" (.3). , , <U (), , .3, =0. , , , ( , ). "", "" U ().
( < 0) ( > a) (0<<a), , . , () : .
-
- (d-) (1) U0, a0, "" "" : aU = const. , (1) , , . a s2 , C " ":
.
:
.
d- 1 C. , , , ( C), .
( ) :
1. =0: Y(+ 0)= Y( 0),
2. =0: Y(+0) Y( 0)= C Y(0), .