Wu Chong-shi
a0a1a2 a3 a4 a5 a6(
a7) a81a9
a10a11a12 a13 a14 a15 a16 (
a17)
§5.1 a18 a19 a20
a21a22a23a24a25a26a27a24a28a29a21a30a23a31a30a23a28a22a23a32
∞summationdisplay
n=0
cn(z ?a)n = c0 + c1(z ?a) + c2(z ?a)2 +···+ cn(z ?a)n +···.
a33a26a34a35a36a37a38a39a31a30a23a28a22a23a32a40a26a41a42a43a44a41a25a45a31a34a35a30a23a28a22a23a46
a47a48 5.1 Abel(
a49a50) a47a48 a51a52a22a23
∞summationtext
n=0
cn(z ?a)n a53a54a55 z0
a56a57
a32a58
a53a59a a55
a29a60a61a32
|z0 ?a|a29a62a63a31a60a64a65a66
a56a57
a32a67
a53 |z ?a| ≤ r(r < |z0 ?a|)
a68
a34a69
a56a57
a46
a70 a71a29
∞summationtext
n=0
cn(z ?a)n a53z0
a56a57
a32a72a34a73a74a75a76a77a78a79
limn→∞cn(z0 ?a)n = 0.
a71a80a81
a53a82
a23 q a32a83|c
n(z0 ?a)n| < q
a46a84
a59
a32
|cn(z ?a)n| = |cn(z0 ?a)n|·
vextendsinglevextendsingle
vextendsinglevextendsingle z ?a
z0 ?a
vextendsinglevextendsingle
vextendsinglevextendsingle
n
< q
vextendsinglevextendsingle
vextendsinglevextendsingle z ?a
z0 ?a
vextendsinglevextendsingle
vextendsinglevextendsingle
n
.
a71a29
vextendsinglevextendsingle
vextendsinglevextendsingle z ?a
z0 ?a
vextendsinglevextendsingle
vextendsinglevextendsingle < 1
a85|z ?a| < |z0 ?a|a86
a32
∞summationtext
n=0
vextendsinglevextendsingle
vextendsinglevextendsingle z ?a
z0 ?a
vextendsinglevextendsingle
vextendsinglevextendsingle
n
a56a57
a32a72
∞summationdisplay
n=0
cn(z ?a)na53a60|z ?a| < |z0 ?a|a64a65a66
a56a57
a46
a67a87|z ?a| ≤ r < |z
0 ?a|a86
a32
|cn(z ?a)n| ≤ q r
n
|z0 ?a|n,
a25a23a28a22a23
∞summationtext
n=0
rn
|z0 ?a|n a56a57
a32a72
∞summationdisplay
n=0
cn(z ?a)na53a60|z ?a| ≤ r (r < |z0 ?a|)a68
a34a69
a56a57
a46
a88a89 a90a22a23
∞summationtext
n=0
cn(z ?a)n a53a54a55z1
a91a92
a32a58
a53
a60|z ?a| = |z
1 ?a|a93a94a94a91a92
a46
a70 a45a95a96a97a46a90a22a23
∞summationtext
n=0
cn(z ? a)n a53a60|z ? a| = |z1 ? a|a93
a54
a34
a55 z2
a56a57
a32a58a98 Abel a73
a99a32a22a23a76a100
a53
a60|z ?a| = |z
2 ?a|(|z2 ?a| > |z1 ?a|)
a64
a56a57
a32a101a102a103a104a105a46a72a22a23
∞summationtext
n=0
cn(z ?a)n
a53
a60|z ?a| = |z
1 ?a|a93a94a94a91a92
a46 square
Wu Chong-shi
§5.1 a106
a5 a6
a82a9
a107a108a109a110a107a108a111a112 a113a114a34a115a22a23
a53z
a116a117a118
a31a119a120a34
a55
a32a121a26a77a122
a56a57
a32a77a122
a91a92
a46a71a80a32
a66a114a21a22a23a123a124a32a125a126a127a128a33a129a31a130a131a132
a53z
a116a117a118
a34a133a134
a55
a21a22a23
a56a57
a32
a53a135
a93
a34a133a134
a55
a21a22
a23
a91a92
a46a33a136
a56a57
a55
a101
a91a92
a55a137a138
a81
a53
a34a115a134a139a140a46
star a141a142Abela73a99a32a33a115a134a139a140a34a73a26a60a46a33a115a60a32a125a143a29a21a22a23a31 a107a108a109a46
star
a56a57
a60a31a60a61a132 z = a
a55
a46
star
a56a57
a60a31a62a63a143a29a107a108a111a112a46
a56a57
a62a63a144
a59
a260a46a33
a86
a32
a56a57
a60a145a146a29a34a115
a55
a46a147z = a
a55
a93
a32a21a22a23
a53a148
a116a117a94a94
a91a92
a46
a56a57
a62a63a40a144
a59
a26∞a46a33
a86
a56a57
a60a125a26
a148
a116a117
a46a21a22a23
a53a148
a116a117
a56a57
a32a149∞
a55a150
a73a26a151
a55
a46
a152a21a22a23a31
a56a57
a62a63a31a153a97a32a25a45a31a154a155a115a132
1. a141a142Cauchya156a157
a97a32a87
limn→∞|cn(z ?a)n|1/n < 1 a85 |z ?a| < 1lim
n→∞|cn|
1/n
a86
a22a23a65a66
a56a57a158
a87
limn→∞|cn(z ?a)n|1/n > 1 a85 |z ?a| > 1lim
n→∞|cn|
1/n
a86
a22a23
a91a92
a46a71a80a32a21a22a23
∞summationtext
n=0
cn(z ?a)n a31
a56a57
a62a63a26
R = 1lim
n→∞|cn|
1/n = limn→∞
vextendsinglevextendsingle
vextendsinglevextendsingle 1
cn
vextendsinglevextendsingle
vextendsinglevextendsingle
1/n
.
2. a141a142d’Alemberta156a157
a97a32a51a52
limn→∞
vextendsinglevextendsingle
vextendsinglevextendsinglecn+1(z ?a)n+1
cn(z ?a)n
vextendsinglevextendsingle
vextendsinglevextendsingle = |z ?a| lim
n→∞
vextendsinglevextendsingle
vextendsinglevextendsinglecn+1
cn
vextendsinglevextendsingle
vextendsinglevextendsingle
a81
a53
a32a58a87
limn→∞
vextendsinglevextendsingle
vextendsinglevextendsinglecn+1(z ?a)n+1
cn(z ?a)n
vextendsinglevextendsingle
vextendsinglevextendsingle < 1
a85 |z ?a| < limn→∞
vextendsinglevextendsingle
vextendsinglevextendsingle cn
cn+1
vextendsinglevextendsingle
vextendsinglevextendsingle
a86
a22a23a65a66
a56a57a158
a87
limn→∞
vextendsinglevextendsingle
vextendsinglevextendsinglecn+1(z ?a)n+1
cn(z ?a)n
vextendsinglevextendsingle
vextendsinglevextendsingle > 1
a85 |z ?a| > limn→∞
vextendsinglevextendsingle
vextendsinglevextendsingle cn
cn+1
vextendsinglevextendsingle
vextendsinglevextendsingle
a86
a22a23
a91a92
a46a71a80a32a21a22a23
∞summationtext
n=0
cn(z ?a)n a31
a56a57
a62a63a26
R = limn→∞
vextendsinglevextendsingle
vextendsingle cnc
n+1
vextendsinglevextendsingle
vextendsingle.
a159a160a161a162a163a164a165a166a167a168a169a170a171a172a173a174a46Cauchya168a169a175a176a177a178a179a167a32a180d’Alemberta168a169
a181a175a171a182a183a167(
a184
a162a185a186 lim
n→∞|cn/cn+1|a187a188)
a46
a189a190a191a192a193a194a195a196
a32a197a197a198a199a200a201a202a203a46
Wu Chong-shi
a0a1a2 a3 a4 a5 a6(
a7) a83a9
a113a114a21a22a23
∞summationtext
n=0
cn(z ?a)n a31a204a34a28a205a26 z a31a206a207a30a23a32Abel a73a99a208a209a210a211a32a21a22a23a53a212
a56
a57
a60a64a119a34a213a214a215
a68
a34a69
a56a57
a32a71a80a32
a141a142 4.2a216
a32
a53
a56a57
a60a64a32a21a22a23a217a218a128a34a115a206a207a30a23 (
a219
a220a124a32a21a22a23a31a221a30a23
a53
a56a57
a60a64a206a207) a32a144
a59
a66a21a22a23a222a28a223a134
a219
a222a28a152a224a23a32
integraldisplay z
z0
∞summationdisplay
n=0
cn(z ?a)n dz =
∞summationdisplay
n=0
cn
integraldisplay z
z0
(z ?a)n dz
=
∞summationdisplay
n=0
cn
n + 1
bracketleftbig(z ?a)n+1 ?(z
0 ?a)n+1
bracketrightbig,
d
dz
bracketleftbigg ∞summationdisplay
n=0
cn(z ?a)n
bracketrightbigg
=
∞summationdisplay
n=0
cnd(z ?a)
n
dz
=
∞summationdisplay
n=0
cn+1(n + 1)(z ?a)n.
star a21a22a23a53
a56a57
a60
a118
a31
a56a57a225a226
? a144a59a94a94
a56a57
a32
? a144a59a94a94
a91a92
a32
? a40a144a59a53a34a133a134a55
a56a57
a32
a53a135
a34a133a134
a55
a91a92
a46
1 + z + z2 +···+ zn +··· a53|z| = 1a118a94a94
a91a92a158
z
1 +
z2
2 +
z3
3 +···+
zn
n +···
a53|z| = 1
a118
a147z = 1
a93a227
a56a57
a32a67
a53 z = 1a55
a91a92a158
z2
1·2 +
z3
2·3 +
z4
3·4 +···+
zn
n(n?1) +···
a53|z| = 1
a118a94a94
a56a57
a46
a228a229a230a35a130a131a32a21a22a23a31
a56a57
a60
a118
a121
a150
a73a154a151
a55
a46
a149
a85
a83
a53
a151
a55
a32a21a22a23a231a100a144a232a26
a56a57
a31 (
a85
a154a233a73a31a30a23a234) a46
a103a21a22a23
∞summationdisplay
n=0
cn(z ?a)n a53
a56a57
a60a64
a56a57a235
f(z)a32a51a52a22
a23
a53
a56a57
a60a236
a118
a54a55 z0
a40
a56a57
a32a221a29S(z
0)
a32a58 a237a238a239
a49a240
a47a48(a228a96) a208a209a210a211a32a87 z a113
a56a57
a60a64a241a114 z
0 a86
a32a242a77a243a244
a53a59z0
a29a245
a55
a44a246a247a292φ < pia31a248a249a64(
a250a2515.1)a32f(z)a125
a34a73a241a114S(z
0)
a46 a252
5.1 a253a254a255a8a0a1a2
Wu Chong-shi
§5.2 a3a4a5a6a7a8a9a10a6a11a12a13 a84a9
§5.2 a14a15a16a17a18a19a20a21a17a22a23a24
§5.3 a68
a154a25a30a23a22a23a206a207
a225
a31a26a229a32a40a144
a59
a45a123a27a229a28a29a30a31a95a25a223a134a31a206a207
a225
a46
a47a48 5.2 a103
1. f(t,z)a175ta31z a167a32a33a34a35a32 t > aa32z ∈ Ga32
2. a36a37a38a39t ≥ aa32f(t,z)a175Ga40
a167a202a41a42a43a34a35a32
3. a44a45
integraldisplay ∞
a
f(t,z)dta188Ga40a46a47a163a164a32a48?ε > 0a32?T(ε)a32a190T2 > T1 > T(ε)a196a32a171
vextendsinglevextendsingle
vextendsinglevextendsingle
vextendsingle
integraldisplay T2
T1
f(t,z)dt
vextendsinglevextendsingle
vextendsinglevextendsingle
vextendsingle < ε,
a58F(z) =
integraldisplay ∞
a
f(t,z)dta53G a64a26a206a207a31a32a49
Fprime(z) =
integraldisplay ∞
a
?f(t,z)
?z dt.
a70 a119a50a34a115a51a52a53a54{a
n}
a0 = a < a1 < a2 < a3 < ··· < an < an+1 < ···, limn→∞an = ∞.
a55u
n(z) =
integraldisplay an+1
an
f(t,z)dta32a58a141a142 3.7a216
a25a114a28a29a30a31a73a223a134a31a206a207
a225
a31a73a99a32a144a56u
n(z)
a26G a64
a31a57a234a206a207a30a23a46a58a71a29
F(z) =
∞summationdisplay
n=0
un(z)
a53G
a118
a34a69
a56a57
a32a72
a141a142 Weierstrassa73a99a32a56
F(z) =
∞summationdisplay
n=0
un(z) =
integraldisplay ∞
a
f(t,z)dt
a53G
a64a206a207a32a49
Fprime(z) =
∞summationdisplay
n=0
uprimen(z) =
integraldisplay ∞
a
?f(t,z)
?z dt. square
a66a114a28a29a30a31a59a223a134a40a144
a59a60a61a62
a94
a99a46
a53a63
a45a33a115a73a99
a86
a32a64a77
a156a65a66a67
a223a134(
a219
a59a223a134)a26a68a34a69
a56a57
a46a25a45a31
a156a157
a97a26a132a69a70
a187
a188
a34a35φ(t)a32a71a72|f(t,z)| < φ(t)a32z ∈ Ga32a180a73
integraldisplay ∞
a
φ(t)dta163a164a32a181
integraldisplay ∞
a
f(t,z)dta188Ga40a74a36
a180a73
a46a47
a163a164a46
a75a29a28a29a30a31
a66a67
a223a134a31a34a115a76a77a32a78
a117
a27a229a223a134
F(z) =
integraldisplay ∞
0
e?t2 cos2ztdt. (5.1)
a33a115a223a134
a68
a31a79a223a30a23a80a100a74a75a73a99a31a81a155a115a78a79a32a67a49a71a29a66a114a82a23 z = x + iy a32a154
|cos2zt| =
radicalBig
cosh22yt?cos22xt ≤ cosh2|yt| ≤ e2|yt|.
Wu Chong-shi
a0a1a2 a3 a4 a5 a6(
a7) a85a9
a84
a59
a32a66a114z
a116a117a118
a31a119a120a34a115a213a214a215
a118
a32 |Imz| < y
0
a32a114a26a32
vextendsinglevextendsingle
vextendsinglee?t2 cos2zt
vextendsinglevextendsingle
vextendsingle < e?t2+2y0t,
a67a223a134
integraldisplay ∞
0
e?t2+2y0tdt
a56a57
a32a84
a59
a28a29a30a31
a66a67
a223a134 (5.1)a34a69
a56a57
a32a71a80a32a33a115a223a134a75a29 z a31a30
a23a32
a53z
a116a117a118
a31a119a120a34a115a214a215a64a206a207a46a83a84a34a85a32a125a154
Fprime(z) = ?
integraldisplay ∞
0
e?t22t sin2ztdt
= e?t2 sin2zt
vextendsinglevextendsingle
vextendsingle
∞
0
?2z
integraldisplay ∞
0
e?t2 cos2ztdt = ?2zF(z).
a206a33a115a86a134a87a88a32a125a144
a59a89
a235
F(z) = Ce?z2 a32a212a68
a25a23C a26
C = F(0) =
integraldisplay ∞
0
e?t2dt = 12√pi,
a33a129a32a41a90a125
a89
a235 integraldisplay ∞
0
e?t2 cos2ztdt = 12√pie?z2.
Wu Chong-shi
§5.3 a11a12a91
a6
a6 Taylora92a93 a86a9
§5.3 a22a23a94a20a17 Taylor a95a96
a46
a161a97a34a35
a188a98
a167a163a164a99a100a101a102
a46
a161a42a43a34a35a46
a69
a39a103a46
a161a42a43a34a35a102a104a178a97a105a35
a226
a47a48 5.1 (Taylor) a103a30a23 f(z)
a53a59 a
a29a60a61a31a60C a64a106C
a118
a206a207a32a58a66a114a60a64a31a119a107 z
a55
a32f(z)a144a45a21a22a23a108a109a29 (
a219
a220a124a32 f(z)a144
a53aa55
a108a109a29a21a22a23)
f(z) =
∞summationdisplay
n=0
an(z ?a)n,
a212
a68
an = 12pii
contintegraldisplay
C
f(ζ)
(ζ ?a)n+1dζ =
f(n)(a)
n! ,
C a50a110a86a111
a87a112a113a46
a70
a141a142Cauchya223a134a114a39a32a66a114a60C a64a119a120a34a55 z a32a154
f(z) = 12pii
contintegraldisplay
C
f(ζ)
ζ ?zdζ.
a149a26a32
1
ζ ?z =
1
(ζ ?a)?(z ?a) =
1
ζ ?a
∞summationdisplay
n=0
parenleftbiggz ?a
ζ ?a
parenrightbiggn
.
a80a22a23
a53
vextendsinglevextendsingle
vextendsinglevextendsinglez ?a
ζ ?a
vextendsinglevextendsingle
vextendsinglevextendsingle ≤ r < 1a31a214a215
a68
a34a69
a56a57
a32a71a80a144
a59
a222a28a223a134a32
f(z) = 12pii
contintegraldisplay
C
bracketleftBigg ∞summationdisplay
n=0
(z ?a)n
(ζ ?a)n+1
bracketrightBigg
f(ζ)dζ
=
∞summationdisplay
n=0
bracketleftbigg 1
2pii
contintegraldisplay
C
f(ζ)
(ζ ?a)n+1dζ
bracketrightbigg
(z ?a)n
=
∞summationdisplay
n=0
an(z ?a)n,
an = 12pii
contintegraldisplay
C
f(ζ)
(ζ ?a)n+1dζ =
f(n)(a)
n! . square
a124a115a132
1. a73a99a31a78a79a144a59a116a117a32a242a77 f(z)a53C a64a206a207a85
a144a46
a159a196
a36a37a118a119
a167 z a32a120a121a122a122a
a123
a99a124a125
a46
a99Cprime a32
a103z a126a127a188
a99a100a46 f(z)
a188Cprime a100a128
Cprime a40
a175a42a43a167a46
a113 a129a130a131a132a133a134a135a136a137a138a139a140a141a131a129a142a136a143a144a145a146a147a148a149a150
Wu Chong-shi
a0a1a2 a3 a4 a5 a6(
a7) a87a9
2. a33a151Taylora108a109a31a38a39a221a152a153a30a23a68
a31 Taylora114a39a154a155a32a149a26a78a79a228a155a46
star a53a152a153a30a23a68
a32 f(x) a31a119a107a156a224a23a81
a53
a32a157a228a75
a59
a243a96 Taylora114a39a81
a53 (
a219 Taylora114a39
a56
a57
)a46
star a53a82a153a30a23a68a32a206a207a31a77a152 (a34a156a224a23a81a53) a125a75a59a243a96 Taylora22a23
a56a57
a46
3. a107a108a158a159 a30a23f(z)a31a151a55a160a148a161a73a128 Taylora22a23a31
a56a57
a62a63a46a103 ba26f(z)a31a162 a
a55
a41
a163a31a151
a55
a32a58a34a164a124a123a32
a56a57
a62a63 R = |b?a|a46
f(z)a188
a99|z ?a| < |b ?a| a100a165a165a42a43a32f(z)a121a122
a188
a99a100a166a167
a123Taylora105a35(a168
a192a169
a32
Taylora105a35a188
a99|z ?a| < |b?a| a100a163a164)a46a159a170a175a169a32f(z)a167Taylora105a35a163a164a165a166a171a172
a37|b?a|
a46
a163a164a165a166
a46a173a174
a171a193a175
a37|b?a|a46a176a181a32ba174a170a126a177a188
a163a164a99a100a32a178a180a97a105a35
a188
a163a164
a99a100a165a165a42a43a32a179 ba174
a123a180
a174a167a181a182a183a184 (
a185a186ba174a175a121a187a180
a174a32a188 5.5
a189)a46
1
1 + z2 =
∞summationdisplay
n=0
(?)nz2n, |z| < 1.
a30a23a31a151
a55 z = ±i
a125
a161
a73a128Taylora22a23a31
a56a57
a62a63 R = |±i| = 1a46
a67
a53
a152a23a248a249a64a32 Taylora22a23a31
a56a57
a62a63a101a30a23
a225a190
a137a138
a31a191a192a125a193
a59
a27a229a46
1
1 + x2 =
∞summationdisplay
n=0
(?)nx2n, ?1 < x < 1,
a125a193
a59
a99a206
a56a57
a62a63a29a107a261a32a71a29a30a231/(1+x2)
a53a194
a115a152a195
a118
a205a26a196a197a144a224a44a198a49a119a107a156a224a23
a205a26a81
a53
a31a199
4. Taylor a200a201a202a203a50a204 a205
a73a34a115
a53
a60C a64a206a207a31a30a23a32a58a206a31 Taylora108a109a26a207a34a31a32
a85
a108a109a192a23a
n
a26
a160a148
a233a73a31a46
a70 a208a73a154a155a115 Taylora22a23
a53
a60C a64a205
a56a57a235
a155a34a115a206a207a30a23 f(z)a32
f(z) = a0 + a1(z ?a) + a2(z ?a)2 +···+ an(z ?a)n +···
= aprime0 + aprime1(z ?a) + aprime2(z ?a)2 +···+ aprimen(z ?a)n +···.
a50a209a210z→aa32a58a113a114a22a23
a53 C
a64a31a119a34a213a214a215
a68
a34a69
a56a57
a32a72a154
a0 = aprime0.
a222a28a86a211a32a212a50a209a210 z → aa32a58
a89
a1 = aprime1.
a51a80a213a197a32
a85
a144a96
a89
an = aprimen, n = 0,1,2,···. square
Taylora108a109a31a207a34
a225
a208a209a210a211a132
Wu Chong-shi
§5.3 a11a12a91
a6
a6 Taylora92a93 a88a9
star a228a229a45a214a122a87a97a32a89
a235
a31f(z)
a53
a155a34a115a60a64a31Taylora108a109a26a207a34a31a46a71a80a32a228a34a73a77a45a152
a224a23a31a153a97a73a108a109a192a23a46
star a51a52a53a155a34a55a108a109a31a155a115Taylora22a23a154a215a32a58a144a59a222a28a216a217a192a23a46
? a76a218a26a53a155a34a55a108a109a31a155a115 Taylora22a23a154a215a32a219a144a59a222a28a216a217a192a23a46
? a155a34a115a30a23a53a228a155a55a108a109a89
a235
a31a155a115Taylora22a23a32
a85
a83a154a114a220a31
a56a57
a214a215a32a40a228a232a221
a222a216a217a108a109a192a23a46