ace academy notes of complex variables for gate and ese with examples
HarshPant18
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103 slides
Aug 14, 2024
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About This Presentation
complex numbers
Size: 7.13 MB
Language: en
Added: Aug 14, 2024
Slides: 103 pages
Slide Content
COMPLEX VARIABLES
Complex number :
no a ow *
ÆNcrf complet mumker can be
represented im a form 2: KH -Cay
whee y are real numbers.
L£NEr] com
ach the
eL mumier 3. X+J make some emsle xe)
post HVE dueclion 4 X- axcy called a (08)
amp le bade La Complex umber fre lr Vay" à
called modalus (ar) absolute value A a complex Be,
Ficoding argument day
From the cag ram sinb= 2» 66> A =>70m0= I
o Y x
36: Tom! (4) y the als Fae:
pler form ue hove 4: x4ly
= HCAOET SEND = ¥C CBO FSO?
- x el
al ere? 5 Ic paler form F 3: 24
pta nd ‘i dy ba
comfez mumier ¡hem Ihe -
y $ 4 denoteÀ by 3-2 re)
proper tes € miles (4 13-2] 7 141-181
4 AE 12, (à) # lar att lanai’: 2( 1st lJ
+ |4)- a it 1240 A ay ica
33 = GAY
A + a; < ide asl AN
lar
observahions on aime a)
a te
ars CAY) = Tan ne
2
7
Here Jane = 32 Jane= !
= 79 (9%) +1
algo Ton (27+) = |
Tan nC amt Th) =|
Tan (enmF)=1 dos W20.2,-°
ade Oh pou d a a a 207
you Le Ep 4 a e A
a fal 4 3 5 ag ds BtanT for m201%
Cc A SN
Here 82 Asa is called principal value 4 any 3
Generally [1 < ang 447 |
oherva Kon
PATAS
Ag CH) > Ars 01)
Tond= 42) Ten 6-1
>) 9-1
: 4
a)
«y
. @= Toms! (à)
Ars Citi) = AX Cu)
Ton 0: >"!
> 70m CA) = "|
49-1 x nt
correr
" Fad) (1-4) 24
oe Ton! (1) +7
EN ‘
=, +
* Ars (x4%0) 20 tf x70
iT if x60
# ag (etiy) : FY yro
Mp Y y<0
# as (ot!) = mt port ble
&) principal value 7 aquel € yee
22 -V3 += (ERED =|)
A Hore
= TO 2 =
E Genera] value 4 agament € 14830
sh Here 3- I+Bi= C3)
General value E ang gs ras! (2) +297
Mat any ! ned215-
>
*
proper fies € ¿ encia] value q argument
A CB... An) = E ~~ +05 Ry
ang (2): ag 4,- any à
arg ca) = naná
ay Ge - 21 Ca)
# AT Cay 4 dm) = ABTA A - - HG bn + 207
for n-où-l Al
Lis” ee Ag AGAR for me OAI
4 Ag a= KAng CA) +2nT fos n=0 a IA
* AS a - Arg (A) +27 for mo &I à -|
@ The Value 4 (y
pr 4- Hi set. zu a a
ST =
Wen Gti) E (e u“ e- rañl(+)= We
oe] oF.
ars
= 254 [esar+ isto 4m)
= 206 (1409)
observation
t+ompt e
Ke ZI for ne 0y1,3- - = Iti@=t
+ (anti rt 2 my CSM ET
A GntDri for 9 20)0123- - ee
il,
FE == + is_nn
Hal = -1+ 1 @)=-1
+ = = a Per Et
e += com) isto Th
= otic: à
&
e
* ®
iit
RE hen the value & it
ip
>
qe 7 (A,
Ma
ae
ae
Fem he real past 4 Pa
qt
4 =
ROLE „sr
“Ug 4)
ot = ase es fe Clgo - is do)
Now veal part q 44T = ase co list)
(aa = m (34
O. cas i900
. » q es )
Ægnaken q cirde im complex form safe
( 2 AR):
, E
he egueñon 4 a circle wh centre ee
4, Au) with yadius +' cs
(2-2): Y Equation $ cirde &
S y
volticafion : 13-Z=r @-ay't -W > Y
> [@+1y)- iti) Y
> lx) cy-wl=r
4 SENSE
laa VA (Yi) 2 7
Ed 13-5-5)= 2 13-5+2c)= 1
= |a-(3-2D]=1
En [a+] 2
2 |2-cstsUlza all
ct al ps
€) = WH
a ga)
À an)
Tf 2- Y ¿CAD im 2- plot they fhe complex June
corres por to 2- Atly can le corten En a forn
fale ario im W-plane. Herr UV art Yeal valued
fomchon, $ Loy
& $: 3Y- Hay”
za)
a v
ED Ya: lay (ED fay: sing
ED Ya: lay (ED fay: sing
ma ie
: les ore” ) ie = semCatiy)
= log 74 (ge = Sina cH CE) + BE sim (13)
- lgr+ie = sina c&hy +0 x Smhy
> eV AA oes
E lg Cat) + ron (4) u 60]
0 an
u
(374 = cah2
sim ia: ¿mba
Periva tive d a Compler function
A complex function fa) ès sud to le
. . 42
difer embiable at 3za |
Le WIKI exist. 74 is embed by Hla)
da ¿ua l
(a: q Be ee Usp nou
A Ja fur) „ U- AAA (a: a”
ler Er 7-0) on ET ya) > 22
Le (24010) Par - aux)
= (ri) +0) =24+2
= 2+2t
. D
& fa: x5
Brno ale
£ (a): an”
Ihre {'(2) dees mer exist at A=2-
FQ mt differential at azo bot US diftrenKable eu
all values opor hom 4-2
Note :
* fu): sina
fu): BA are diff ren hioble evezy hese
£CA)= eA
a
fa) = €
* polynomial fonctions are differentiable e veryuhere
£a: fu): 143844: Ya): 242 de
at every point m hole complex plume
> jar: a & Aipprentiobe everyakert-
Fxg) Ya): àt3
ED ES) ga: 2(3maz)
= a-ty+3 c
ip =
v a oy
Vas 1? Vaio Uq=¥ : V0
Uy=0 2 Bye A : By 22
Fer Unt By at all points on were c-2 egpalions
salts fied ar (09 on
cohde complex far
. a E . 43) is diferenk able of
.. faj=4+3 5 moler differentiable a soit €
nok: 34 fear mio yy diffembioble they
4102) = U + dx
2 Ugtt Uy) [- Uy =-%]
2 Bytit, [o my)
CR eguaticos in poler Ferm
4 49. ano ino) & Aiferenkoble then
wee eo (Hs +58)
Up: -y Vr (2%: -r à)
Amaly Ke functor
A complex fun chon fa) Y said to be
analy fic at gza it { da) &
differen Hable at every pol within som
d- disc 4 3-9
Key potas
# analytic fumetions are algo called regular (en holomorphi<
func Hons
x A fume Kon which y amaly tic every here m cole complex plane
is called entire fanction
+ Amalyfc fanchon is infinitely differentiable
# Tf tig are analpfic gunchow they 143, 17, § alse
fic fumchons
* pmalyhic funchen is alow differenhable bur differen Hable
funckon red mg de analytic:
observa Ron
ET a
x
f(a)- e ze ICE & amaly le)
ee
cet Coes ti siny)
lex Urt Uyy O
5 u_ Su _o CS
be FUN TL TO
A Y y
stm lary Var Vyy =? ) ACTE
clearly W% sah fies op (acter,
espahon 8 -o
Wand Y are harmonic Yumchorg
=e chy +i eTsiny
un <<
U D
Y Lay: Uy: = * siny
Aa : Ac&y à: Uyy = A chy
WKY If yrg-o mem Bis called
harmonic fumchon
Note. Jf ARS UA iO à amalyfe Fm vuz0 and 0-0
4 vand Y are harmonic funchens amd ‘v' is called
harmonie comjug ate Ku
24 fa)= U+i0 y amalyhe and if u à give
BPP = ae i a)
=> Fimd Var Uy
> 92 fonder fra Au
fort
yan Sen
KH): Uti ds analyke and | VEAP
m m —LÉ nn
> Find Vy vy
=> Me S ryder hr +k
+ y cont gern SA
nets
70 write Ihc
amaly Ke fumch'e
far atid lo
kom € 2
pat x=3 and y=0
cm u Y
En) For am analytic fumchioo fa): uo, f Me veal part
Us 2x. find cts harmonic comjuzar Y
sl Gem u: XP TA co
Un- 2142: Uy =-2) 70 wrıf fa) mkrms ÿ 2
Pst X=3 and yzo im UN
ale + dy +15
Now) »-) y Az Sun 7 Ur a 2a: peotork
"yimt 175 .
witha Nou) Ya) Ut
3 ve Secada +fady+r = AMHR +61
Ed AGE amalyhe famchen $12) UD cf Uz eX siny fond
a. Algo wrile Yıa) teams f 2
A Giv™ B= e*smy = u: fetcosydx+ fo dy +
a
= er simy a IAS
Vy= ec3y por f(a) pur X=, 720 tn
Wes uf By dat [= Vx dy + wand Y m
PG hon te rer... a. e+e! V0
L sito Now Ya): ui
= 4e
complex ines vatton
HC ig a path bekweem foo pains
AtoB If we define a complex
funcio» along he path 2 from APB,
6. In the Laurent series expansion of He x ade
dos region sl Give Yca) 7 Gnas = 37
Im ROC (513142 (/31<2 amd 13171]
z D Be
ET ah)
Zn AG dC"
1:4 (+ CB) Era >)
“Z(G +4) J
Conff d pe a]
fesidue : IE gra % am Kolated Simgalos polar $ 42) then
(PEE ee coef q tao" Im Laurent Seras 4 fa)
ab Aza
a = mon Be sour por: If Aza Ey a vemovalle
Sémçu larihy (nen fs fea] 0
¿za
@ ja: 53
: e
Hen Alo 5 am iso (ak A Singular pont
Nous Jıal- SYA _ 1
2 Él ES
this expansion confaing mo mega pue pose as & (49
“ aro 8 Yemoalle scm alarily
pele 4 Ae am Bolaked simgu lazikr gza & calkd a
ple order oy fe Laurent Sert §
44) abut 424 comtaim negative proses
apto (4-0) *,
£u 403) - al
a) | . pot 4-17
Here 41 & ¿solajed sogaler pon 2: I1k
HE _ ¿er
ns fu): E 7 LE: Lo
A) [24 er ES rt )
2
ha) -
2 La
3 ES
El
e
21 a
ao
=
mo
= fe
HE
Ze
ca
el ae
@
ek ie or
= fe “
“5 | ‘
. 8! ca
a ; D+ =
ql ays
Y .
Nofe! pl & Ed
€
order m
4 4
iS
8 cale
fe Y x A
e
pole.
Jaden fication 2 ze omeva ble sing arily and cod hou
Louvrent series
if he given fonction 412): we
3 1 aa y om wolated sims alavity wih multiplicity m'
If 9
cal, Tf $la)to hen da à a pole 4 oer m"
cased: 2% G64) =0, Pica) =9, $'ta)2 0. Papo : compere mm
#24 mom they gra is a pole $ order m”
* A men Men A:a y a rumovalle semgularih
a
Ed) Ja. e +23 . GCA) Ed fcar- 243. da
(4-4)! cart pla) (34) (arr) PA)
Pere pta) 4o amd 615) +0 Here dito amd bn 40
4:4 isa pole 4 order (0:0 asl, 2 or poles § otr
Hr
ds ga pole q order 4
be 42 1-2 ase simple poles.
& fa: sing - és) SE) yar wa : 62)
3° PCR) 302 PA)
A a Singulosily bias Cees Gi ct Singular pdt
u win mai
dia): sima: — Ko +0
62): $2 9 ECM)=0
gim cha HN: ¡+2 3021
ges -sma > 60m) 1+0
her m>n
i mm
4:08 a ple & oder mon: 3422 L Be Y ie moral Singular)
hese nel
Exenfiol Singular point : pn Esolated singular pomt ara es
called am epentiol salat Y IR Aouremt Saris G fa)
abst Ara comfaims infivile nemer € E poux £ Ca-a)
au, ta: Sm(4) G) Ca), Oe ca
his expansion contain imfinte member E neçahw poes
q (4-0) .
320 à esenhal singulorih-
Residue’ 2f ¿a is am isolated sirpulow pone 8 fa then
| residue 4 vn], 2 cacfficient Y Ga” in eurent
za
Series Y fa) at A=a
calculate 2 residus
a
Resi due of aemoy able simgalor pont . 2% dea MA certe
sen alar ly hen (sé), >
ca): SA , dia)
a pia)
Her 4:0 & singular poor ah m=
dia): HPA => £co=0
: 20
$ca). 257052 $190 pesto...
2 SMA
g"ua): zung + $01.240
ale
MEN. ao ig vemovalle siwalen y
pagano of pl ere
ap Ava pole of order E fan
Note!
A
Y“ 664) amd 4
pla)
ee
(res 02) e 4 Abel (ea) 4=a wa simple pole
20 (en) ata 27
# 26 da y a Simple ple len Ez
[Sk Vaca = 4 El (3-1 f{@)
Ltda 2 a C4-a)* ga)
hen [res fan], = 60)
a= a q da)
(E) vesidas E fray: UL „at & ples:
¿na
6 por), ‚tr Lea
curve ‘
outside €
. Sener. dl
sel Gwen circle Y 12-212, I regidues impide €
are ¿ero
By residue heorem
(ca) 430
=
The
value
y =fresfıa | me ES)
2
of INR 4-
a,
axe Gray AaB
5-2 (trey
= (Mette = si-4
Here 32-06 &
a simple ple Ces
mside 0
OS Ihres)
(fanaa = aqix yy
¿E = un (6-4)
- 4mll 3-2)
= 4G (2k- 3)
8 he value wh A 2 + q a 31: L— = &
in y Wa es =
=Lis ur
: EE Al
@) Ai $) 0 >, ¿mL [i a E
{c) -2mi a >
=1f14) - ent Fat 45%
eee) = frs) = cold +
420
Lo = pP
2 = In. AL, ya Al) =
+2: E
wy 13% yr Cr" Ey residue Les
fos aix y
y LA
y 2 zarix)= -277
Let (-1 -j). (3 - j). (3 + j) and (-1 + j) be
the vertice: rectangle C in the complex
plane. Assuming th is tranversed in
counterclockwise direction. the value of the
counter integral $ is (GATE-21)
faye ——
4*(a-4)
Here 8:08 4 pole Y order Y les
inside 'c'
Her Ket
22. An ir 11
circle *C* is
If C is defined as |z| = 3 then the value of 1
is
(a) -zi sin(1) (b) Zi sin(1
(c) —3zi sin (1) (d) — 4mi sin (1)
(GATE-17)
3 (a: EN
Cri X2-Ù)
Her arta ore Sim ple poles lees
inside °c! 3
G- C3A)x Gye
vie [ves fea) LE 3% Can) (aD
= 2 xl - „ziel
Be L -2
E
path C in the complex sá ph La) Es
——
1 in the figure. If
rn am)
Sa OFA is_ (Rounded off to two Yer 4:18 à simple pole les inside e
d e
= Ari
y. E cami] "7 HZ 7%
4 C4/+1) (44)
e ( falda = aix C4): E
= —O0
Given (fa: ATA, 9
(2
Frm DAD AZ
The value o
curve c. where c is |z|=4. is
27 (b) 0
along a pot $ 3)- ESA
<a4)car2)
2 ar Simple poles
Hem 82, -
Cig, inside E
_4
_ 4 (ara
= a = 242
4, {res fc la, ER Gr G2)
2 4
3 —— —
vs [res Bt]. 9 = & oY GH) Cys)
2
Sócaras = agicrtrs)
2211 (142) = 20
Tae ps $31)
3:4
By residue oye
(ete ar x (+72)
€
=amxçiet-iet)
2-2 ¿A
x (ED) yal
al
Ani Sima)
u
261, i, id
Er lá
2
rel
Ze
. 12 -ia
Sim 3 = ee
: ue [> Paria 4 { "ar =] 7
By residue herr om
eee x Tr