f(x) [a; b], [m; M], m M f(x) [a; b].
1.) , .
limn¥xn = A1 limn ¥xn = A2, A1¹ A2, e - A1, A2, . e e = 1/2|A1-A2|. $ N1,N2, n>N1 xnÎU(A1), n>N2 xnÎ U(A2). , n> max{N1,N2} xnÎ U(A1)ÇU(A2), , U(A1)Ç U(A2) = Æ.
2.) , .
= a, = b, cn=xn+yn
=c c=a+b (.. )
= a, xn=+..1
b, yn=b+..2
cn=xn+yn=a+b+..3 ( )
cn .
3) , .
{xn}-...
{yn}-
$M>0 , "n | yn |≤M " ε/M>0, $N , n≥N |xn*yn|=|xn|*|yn|< (ε/M)*M= ε=> {xn}*{yn} .
4.) , (), .
.. , , ux : lim(u1 + u2+... + uk) = lim u1+lim u2 +... +lim uk
. , . lim u1 =a1 lim u2 = a2. ( f(x) b y=b+ , lim y =b( ->a;x->∞))
u1 =a1+α1 , u2 =a2+α2 , α1 α2 ,
u1+ u2=(a1+ a2) +(α1+α2)
.. (a1+ a2)- , (α1+α2) , ( f(x) b y=b+ , lim y =b( ->a;x->∞)),
lim(u1+ u2 )=a1+ a2 = lim u1+ lim u2
.. , ux>0,
5) , {x n } {y n } x n ≥y n, ≥
x n ≥0, ), ≥0.
, b <0, |x n - ≥| |.
.. |x n - b| 0 n->∞ x n b n->∞, b≥0
y n≥0
|
|
x n y n≤0
, x n ≥y n (x n -y n)>0, >0
=> 0
≤
6) .
u≤z≤v, = b; =b,
: u≤z≤v , u-b ≤z-b ≤ v-b, = b; =b, , " ε , |u-b|< ε, , |v-b|< ε
:
ε<u-b< ε
ε<v-b< ε=> ε<u-b< ε=>
7) , 2 ... .
{x n } {y n } ,
{x n }: ">0, $N1 , "n>N1, |xn|>A
{y n }: ">0, $N2 , "n>N2, |yn|>A
N=max(N1,N2)
"n>N : |xn+yn|≤|xn| + |yn|>2A, "A>0,
.. sgn xn≤sgn yn, sgn x =
8) , ...
{an}-... $ >>0, $N , |n|>>M, "n>N, |an|>
{bn} : $1>0, |bn|≤M1, "n .
M>>M1
-|bn|≥-M
|n|-|bn|> 1 -M; " n >0 .. |cn|= |n|-|bn| >(1 M)>>0
"n>N, N , |cn|-...
9) , 2 ... ...
.. {an}-... $ 1>>0, $N , |n|>>M1, "n>N, |an|> 1
.. {bn}-... $ 2>>0, $N , |bn|>>M2, "n>N, |bn|> 2
|cn|=|n|*|bn|> 1* 2>>0, "n>N, N
10) ... ...
{an}-... $ >>0, $N , |n|>>M, "n>N, |an|>
{bn} : $1>0, |bn|≤M1, "n .
M>>M1
|n|*|bn|> 1 *M; " n >0 .. |cn|= |n|*|bn| >(1 *M)>>0
"n>N, N , |cn|-...
11) , ,{x}-
"ε >0 $ N(ε) , "n>N |xn-A|< ε
- ε<xn-A< ε
A- ε<xn< ε+A
Xn->A
12 ) , ,{x}-
>>0, $N , |xn|>M, "n>N, .. , , ε- ∞
|
|
13) , ,f(x)-
"ε >0, $δ(ε)>0 , , 0<|x-x0|<δ
|f(x)-|<ε
14) , ,f(x)-
>>0, N , f(x)>M, "n>N, .. ε- ∞
16.) , .
f(x) g(x) . φ(x)- , ..
φ()= f(x) + g(x). |φ()|>|f(x)| |φ()|>|g(x)|.
..
. φ()- . ...
18.) , .
f(x) g(x) . φ(x)- , ..
φ()= f(x) * g(x). |φ()|>|f(x)| |φ()|>|g(x)|.
..
. φ()- . ...
19.) .
20.) .