3.
: . , . .
, .
.
1. .
.
0, , 0 . , , 0, , = 0, . , 0ÎD(f), 0 .
3.1. 0 . = f (x) 0,
.
, 0
2.1( ), , f (x 0+0) f (x 00) . .
3.1.( )
f (x) 0 , , f (x 0+0) f (x 00)
f (x 0+0) = f (x 00) = f (x 0).
:
1) f (x 0);
2) f (x 0+0) f (x 00);
3) f (x 0+0) = f (x 00);
4) f (x 0+0) = f (x 00) = f (x 0).
, 0 .
, 0 .
3.2.
0 ( ), f (x 0+0) f (x 00), f (x 0+0) ¹ f (x 00).
0 , (, ¥).
0 , f (x 0+0) f (x 00)
f (x 0+0) = f (x 00) ¹ f (x 0).
3.2 , ( 0 ), , . 2 4 .
2, ( 8 , , ).
3, 2 , , 1 (.9, , ), (.9, ).
|
|
w = | f (x 0+0) f (x 00)|
0.
|
2 3, 4 1, (.10)
. . 0 1, ,
D = 1 0.
= f (x)
D = f (x 1) f (x 0) = f (x 0+D ) f (x 0),
1 = 0+D , f (x 0+D ) = f (x 0) + D , , .
3. 3. = f (x) 0, 0Î D(f) , ..
.
, 3.1 3.3 . , , " e > 0 $ d > 0 , " , | x x 0| < d Þ | f (x) f (x 0) | < e. 0 = D , f (x) f (x 0) = D , " e > 0 $ d > 0 , " , |D | < d Þ | D | < e. , .
, , " e > 0 $ d > 0 , " , |D | < d Þ | D | < e, , D = 0 D = f (x) f (x 0), " e > 0 $ d > 0 , " , | x x 0| < d Þ | f (x) f (x 0) | < e. , . .
3.4. , [ a; b ], .
, , .
.
3.2.
.
: , , = + b. (¥, +¥). = 0 , D D
D = ( ( 0 + D ) + b) ( + b)) = D .
, , 3.3, 0, .. .
, = sin x, x Î R. :
,
= sin x .
.
3.3
f (x) g (x) D 0ÎD, f (x) .g (x), f (x) g (x), , g (x 0) ¹ 0.
: ( 2.5).
, f (x) g (x) 0, . , 2.5,
,
0.
, .
3.4.
j() D, f () (j). j() 0ÎD, f () 0 = j( 0), f (j(x)) 0. ( )
|
|
, 3.2, 3.3 3.4.
.
, .
, .
3.4 :
,
.