шамин с сдо
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|f(x) − A| < ε. |
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−∞ |
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f(x) |
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(−∞, a) |
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A |
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x → −∞ |
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ε > 0 |
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M > 0 |
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x < −M |
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|f(x) − A| < ε. |
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arctg(x) |
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lim arctg(x) = π/2, |
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x→+∞ |
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x lim arctg(x) = −π/2. |
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→−∞ |
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x→0 |
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x) |
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1 |
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z |
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= z→∞ 1 + z |
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lim (1 + |
1/x |
lim |
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e |
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1 |
z |
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z→+∞ 1 + z |
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z > 0 |
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lim |
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n N |
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n ≤ z ≤ n + 1 |
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1 |
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1 |
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z |
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n+1 |
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1 + |
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≤ 1 + |
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≤ 1 + |
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n + 1 |
z |
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n |
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1.5 |
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1.0 |
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0.5 |
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x |
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arctan |
0.0 |
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−0.5 |
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−1.0 |
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−1.5 |
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−100 |
−75 |
−50 |
−25 |
0 |
25 |
50 |
75 |
100 |
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x |
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arctg n
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un = |
1 + n1 n |
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z |
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· |
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1 |
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≤ |
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1 |
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≤ |
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1 + n+11 |
z |
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n |
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un+1 |
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1 + |
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un |
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1 + |
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z → +∞ |
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n → ∞ |
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nlim un = e |
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→∞ |
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1 |
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z |
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z→+∞ 1 + z |
= e. |
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lim |
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1 |
z |
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z→−∞ 1 + z |
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lim |
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z = −(t + 1) |
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t → +∞ |
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z → −∞ |
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z→−∞ |
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1 |
z |
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1 |
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−(t+1) |
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z |
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= t→+∞ 1 − t + 1 |
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= |
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lim |
1 + |
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lim |
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t |
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−(t+1) |
t→+∞ |
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1 |
t+1 |
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= t→+∞ t + 1 |
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t |
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lim |
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t |
= lim |
1 + |
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= |
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t→+∞ |
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1 |
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t→+∞ |
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1 |
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t |
· |
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t |
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= lim |
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1 + |
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lim |
1 + |
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= e. |
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f(x)
x → x0
lim f(x) = 0.
x→x0
x0 |
±∞ |
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f(x) |
x → x0 x0 |
±∞ |
xn |
f(x) |
xn → x0 |
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nlim f(xn) = ∞. |
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→∞ |
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I |
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f(x) |
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g(x) |
f |
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g |
I |
C > 0 |
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|f(x)| ≤ C|g(x)|, x I. |
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f(x) = O(g(x)), |
I. |
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f(x) = O(1). |
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f(x) g(x) |
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x0 |
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x0 |
g(x) 6= 0 |
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f(x) |
g(x) |
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x → x0 |
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f(x) |
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lim |
= 0. |
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g(x) |
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x→x0 |
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f(x) = o(g(x)) |
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o(g(x)) |
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f(x) |
g(x) |
x → x0 |
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f(x) |
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lim |
= 1. |
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g(x) |
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x→x0 |
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f(x) ≈ g(x) (x → x0)
I = (0, ∞)
ln x x |
x I |
ln x ≤ x,
ln x = O(x)
P (x)
P (x) = O(ex), x (0, ∞).
m < n
xn = o(xm), x → 0,
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n |
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lim |
x |
= lim xn−m = 0. |
m |
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x→0 x |
x→0 |
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lim sin x = 1,
x→0 x
x → 0
sin x ≈ x.
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1.0 |
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0.8 |
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0.6 |
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sin |
0.4 |
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0.2 |
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0.0 |
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−0.2 |
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−20 |
−15 |
−10 |
−5 |
0 |
5 |
10 |
15 |
20 |
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x |
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sin x x
f(x) |
x0 |
x0
lim f(x) = f(x0).
x→x0
ε > 0 |
δ = δ(ε) > 0 |
|f(x) − f(x0)| < ε,
|x − x0| < δ.
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f(x) |
x0 |
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U(f(x0), ε) |
U(x0, δ) |
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f : U(x0, δ) U(f(x0), ε), |
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x U(x0, δ) |
f(x) U(f(x0), ε) |
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f(x) |
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(a, b) |
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x0 (a, b) |
x |
(a, b) |
x − x0 |
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x = x − x0.
f(x) − f(x0)
y = f(x0 + Δ) − f(x0).
f(x) |
x0 |
lim f(x) = f(x0).
x→x0
lim y = 0.
x→0
f(x) |
x0 |
x x0
y
(a, b]
x0 (a, b]
lim = f(x0).
x→x0−0
[a, b)
x0 [a, b)
lim = f(x0).
x→x0+0
f(x) |
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(a, b) |
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(a, b) |
x0 (a, b) |
f(x) |
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[a, b] |
[a, b] |
(a, b) |
a |
b |
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f(x) g(x)
I
f(x) + g(x), f(x) − g(x), f(x) · g(x),
g(x) =6 0 I
f(x) . g(x)
f(x) |
[a, b] |
M > 0
|f(x)| ≤ M, x [a, b].
M > 0
xM [a, b]
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|f(xM )| > M. |
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M = 1, 2, . . . |
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{xn} |
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|f(xn)| > n. |
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{xnk } |
klim xnk = x0 |
x0 [a, b] |
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→∞ |
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f(x) |
x0 |
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lim f(xnk ) = f(x0). |
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k→∞ |
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