, .
= f (), , = a.
. = f () , a ( a), e > 0 d > 0, ,
0 < | x a | < d, (1)
| f (x) A| < e. (2)
: f () = A.
, = f () (. . 1).
(1) , d, ] a d, a + d[ d- . (2) , = f () ] e, + e [ , e- .
: f () = A1 f () = A2. . A1 A2 , f () ().
, (. . 1) f () = f () = A, = f () = f () = f () = A.
, .
(. . 2.) f () ¹ f (), 1 ¹ 2, (. . 2.), = .
, , ¥.
. = f () ¥, e N , , | x | > N, | f (x) A| < e.
= f () ¥ f () = .
. = f () ( ¥), f () = 0 ( f () = 0).
().
, = ( 3)2 3, ( 3)2 = 0; = ¥, = 0.
.
2.2.1. = f () b ,
() = b + (). : () = b + (), f () = b.
2.2.2. .
2.2.3. .
|
|
1. .
2. .