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Сборник задач по высшей математике 2 том

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BU"I,uc./Ium'b UHme2pa./lU, nepeXOOR 71: nO.II.RpHUM 'lCOOpOUHamaM:

3.2.17.

II Ja2 -

X2 -

y2 dxdy, r,ll;e D - nOJIyKpyr X2 + y2 ~ a2, y ~ 0.

 

D

 

 

 

 

a

~

 

3.2.18.

I dx

I

Jx2 + y2 dy.

 

o

0

 

 

3.2.19.

II Ja2 -

x 2 -

y2 dxdy, r,ll;e D OrpaHHqeHa JIeMHHcKaToit

D

3.2.20. II Jl- :: - ~:dxdy, r,ll;e D- BHYTpeHHOCTb 9JIJIHnCa

D

B c./Ieoytow,ux oao'iJ.Hux UHme2pa./laX paccmaaum'b npeoe.llu UHme2pupoaaHUSJ, npUMe'H..R.R np.R.MoY20./l'bHUe U nO.II.RpHUe cucmeMU 7I:OOpOUHam:

3.2.21.

II f(x, y) dxdy, r,ll;e D OrpaHHqeHa OKPY:>KHOCT1.IMH x 2 + y2 = 4x,

 

D

 

x 2 + y2 = 8x H np1.lMbIMH y = X H Y = 2x.

3.2.22.

II f(x, y) dxdy, r,ll;e D OrpaHHqeHa np1.lMbIMH y = 0, X = 1, y = x.

D

BU"I,uc./lum'b oao'iJ.Hue UHme2pa./lU:

3.2.23.

II(x2 + y2) dxdy, r,ll;e D OrpaHHqeHa KpHBbIMH y = x, X + y = 2a,

 

D

 

X = 0.

3.2.24.

II ';'x-y-_-y"""2 dxdy, r,ll;e D - TpaneU;H1.I C BepIIIHHaMH A(I,I),

 

D

 

B(5, 1), C(10, 2), K(2,2).

3.2.25.

II xy dxdy, r,ll;e D OrpaHHQeHa KpHBblMH X + y = 2, x 2 + y2 = 2y

 

D

 

(x> 0).

3.2.26.

II (X + 2y) dxdy, r,ll;e D OrpaHHQeHa KpHBbIMH y = x 2, Y = ..jX.

D

150

E G)?

j(a'H'H)bte U'Hmeepa.l!'bt 6'bt"tUC.I!Um'b, nepeXOa.H. 11: nO.I!.H.p'H'bt.M. 1I:OOpaU'Hama.M.:

3.2.27.

II J9 - x 2 - y2 dxdy, r,lJ;e D OrpaHH'IeHaKpHBbIMH

y = x, y =

 

D

 

 

 

= V3x, x 2 + y2 = 9.

 

 

3.2.28.

II (x2+y2) dxdy, r,lJ;e D OrpaHH'IeHaOKPy:>KHOCTbIO x 2+y2 = 2Rx.

 

D

 

 

3.2.29.

II dxdy, r,lJ;e D OrpaHH'IeHaJIHHHeii(x 2 +y2)2 = 2ax3 .

 

D

 

 

3.2.30.

II JR2 - x 2 - y2 dxdy, me D - Kpyr x 2 + y2 ~ Rx.

 

D

 

 

3.2.31.

II y dxdy, me D - nOJIyKpyr (x - a)2 + y2 ~ a2, y ~ O.

 

D

 

 

3.2.32.

II (x 2 + y2) dxdy, r,lJ;e D -

Kpyr x 2 + (y + 2)2 ~ 4.

 

 

D

 

 

3.2.33.

II arctg ~ dxdy, r,lJ;e D -

'IeTBepTbKpyra x 2 + y2

~ 1, x ~ 0,

 

D

 

 

 

Y ~ O.

 

 

3.2.34.

II dxdy, me D OrpaHH'IeHaJIeMHHCKaTOii (x2 + y2)2 = 2a2xy.

D

KOHTponbHble Bonpocbl III 60nee CnO)l(Hbie saACIHIIIR'

3.2.35. qTO Bblprur<aeT 3HaK 51Ko6HaHa npeo6pa30BaHH5I KOOp,lJ;HHaT?

3.2.36. IIo'IeMYnpH npeo6pa30BaHHH KOOp,lJ;HHaT B ,lJ;BoiiHOM HHTerpaJIe Heo6xo,lJ;HMa B3aHMHM O,lJ;H03Ha'IHOCTb9Toro npeo6pa30BaHH5I?

3.2.37. IIo'IeMY<PyHKIJ;HH x = x(u,v), y = y(u,v) HCnOJIb3yeMble npH 3aMeHe nepeMeHHbIX B ,lJ;BoiiHOM HHTerpaJIe ,lJ;OJDKHbI 6bITb ,lJ;H<p<pepeHIJ;HpyeMbIMH (npH (u,v)

3.2.38. MO)l<HO JIH BbmOJIHHTb TaKoe npeo6pa30BaHHe, 'ITo6bI COOTBeTCTByIOIu;HM HHTerpaJIOM BbI'IHCJIHTb,lJ;JIHHy KpHBOii?

3.2.39. IIpH COCTaBJIeHHH nOBTopHoro HHTerpaJIa nOJIY'IHJIaCb3anHCb

X 3x 2

Idx I f(x,y)dy.

a 2x-y

KaKoii 06JIaCTH D MO)l{eT COOTBeTCTBOBaTb 9TOT HHTerpaJI?

B aa'H'H'btx a60il.'H'btX U'Hmeepa.l!ax nepeil.mu 11: no.I!.H.p'H'bt.M. 1I:OOpaU'Hama.M. U pacCma6Um'b npeae.l!'bt U'HmeepUp06a'HU.H.:

3.2.40. II f(x, y) dxdy, D - Kpyr x 2 + y2 ~ ax.

D

151

3.2.41.

JJI(x, y) dxdy, 06JIaCTb D - o6rn;ruI 'IaCTbKpyroB x 2 + y2 ::;; ax,

 

D

 

x 2 + y2 ::;; bx.

3.2.42.

JJI(x, y) dxdy, 06JIaCTb D OrpaHH'IeHaIIpHMbIMH y = -x, y = x,

D

y=l.

B aa'lt'H!btX UHme2pa.ll.aX npOU36ecmu Y'ICa3aHHY'lO 3aMeHY nepeMeHH'btX U pacCma6Um'b npeae.ll.'bt UHme2pUp06aH'U.R.:

 

b

/3x

3.2.43.

Jdx

JI(x, y) dy (a> 0, a > 0), eCJIH U = x, v = ~.

 

a

ax

 

1

1

3.2.44.

Jdx

JI(x, y) dy, eCJIH U = x + y, V = X - y.

o 0

3.2.45.JJI(x, y) dxdy, me D - 06JIaCTb, OrpaHH'IeHHaHKPHBOii

D

(X2 + ly2)2 = x 2y,

 

eCJIH x = r cos <p, y = V3r sin <po

 

 

 

3.2.46.

JJI(x, y) dxdy, r,!l;e D OrpaHH'IeHaIIapa60JIaMH y = ax2, y = by2

 

D

 

 

 

eCJIH y = ux2, xy = v (0 < a < b,

 

H rHIIep60JIaMH xy = p, xy = q,

 

0< p < q).

 

 

 

 

 

3.2.47.

TIpeo6pa30BaTb C IIOMOlII,bIO IIO,!l;CTaHOBOK x = ar cos <p, y = br sin <p

 

HHTerpaJI

 

 

 

 

 

 

 

 

JJ1(R2 - :~ -

~:) dxdy,

 

 

 

 

D

 

 

 

 

 

r,!l;e D - JIe)Karn;ruI B IIepBoii 'IeTBepTH 'IaCTb 9JIJIHIITH'IeCKOrO

 

KOJIbIJ;a

 

 

 

 

 

JIepe11mu

'IC nOJlJlpH'bt.M

'lCOOpaUHamaM (r, <p) U pacCma6Um'b npeae.n.'bt UHme-

2pUp06aH'U.R. 6 mOM U 6

apY20M nopSla'ICe 6

aaHH'btX UHme2pa.ll.ax:

 

1

1

 

 

 

1

~

3.2.48.

Jdx

JI(x, y) dy.

3.2.49.

J

J I(x,y) dy.

dx

 

 

 

 

0

0

 

 

 

0

i-x

 

2

xv'3

 

 

 

 

 

3.2.50.

J

JI( Jx 2 + y2) dy.

 

 

 

 

dx

 

 

 

 

 

0

x

 

 

 

 

 

152

3.2.51.B ,!l;BOtiHOM HHTerpaJIe

IIf(x,y)dxdy,

D

 

r,!l;e 06JIaCTb D OrpaHH'IeHaKpHBbIMH ..;x+vY = va, x = 0, y = 0,

 

C,!l;eJIaTb 3aMeHY nepeMeHHblx x = U cos4 V, Y = U sin4 v. HHTerpaJI

 

npHBeCTH K nOBTopHOMY.

 

 

 

3.2.52.

BbI'IHCJIHTb

II dxdy,

 

 

 

 

 

 

 

 

D

 

 

 

 

 

x2

y2

X

Y

 

r,!l;e D OrpaHH'IeHaKPHBOti a2

+ b2 = Ii

+

3.2.53.

BbI'IHCJIHTb

II dxdy,

 

 

 

 

Vf = 1, x = 0, y = o.

 

 

D

VI +

 

r,!l;e D OrpaHH'IeHaKpHBbIMH

3.2.54.

BbI'IHCJIHTb

II r21sin (<p + ~f) - rl

 

 

 

 

drd<p,

 

 

D

 

 

 

 

r,!l;e D - npHMoyrOJIbHHK 0 ::;; r ::;; 1,

0::;;

<p ::;; 21f.

§ 3. np~MEHEH~SI ABOIf1HOrO ~HTErpAJlA

.II:Boil:Hble HHTerpaJIbI HCIIOJIb3YIOTCH IIpH peIIIeHHH MHorHX reOMeTpH'IeCKHXH <pH3H'IeCKHX3a,II;a'l:BbI'IHCJIeHHHllJIOIrrap;eil: llJIOCKHX <pHryp H 1I0BepxHocTeil:, 06'b- eMOB TeJI, Koopp;HHaT rreHTpa TH:lKeCTH, MOMeHTa HHeprrHH H T. p;.

1. ECJIH D - OrpaHH'IeHHaH06JIacTb llJIOCKOCTH Oxy, TO ee llJIOIIIa,II;b S BbI-

QHCJIHeTCH 110 <p0pMYJIe

 

S = S(D) = Ildxdy.

 

D

2. TIYCTb Z = I(x, y) -

HeoTPHrraTeJIbHaH, HellpepbIBHaH <pYHKrrHH B 3aMKHY-

Toti 06JIacTH D. ECJIH V -

TeJIO, OrpaHH'IeHHOecBepxy 1I0BepXHOCTbIO Z = I(x,y),

CHH3Y - OMaCTbIO D, a

C60KY - COOTBeTCTBYIOIIIeil: rrHJIHHp;pH'IeCKoil: 1I0Bepx-

IiOCTbIO C 06pa3yIOIIIeil: lIapaJIJIeJIbHoil: OCH Oz H HallpaBJIHIOIIIeil:, COBlla,II;aIOIIIeil: C rpaliHrreil: 06JIacTH D, TO 06'beM3TOro TeJIa paseH

V= 111(x, y) dxdy.

D

3. TIYCTb V - TeJIO, OrpaHH'IeHHOecBepxy 1I0BepXHOCTbIO Z = I(x, y), CHH3YnoaepxHocTbIO Z = g(x, y), IIpH'IeMIIpoeKIIHeil: 06eHx 1I0BepxHocTeil: Ha llJIOCKOCTb

153

Oxy CJIY:lKHT 06JIacTb D, B KOTOPOit <PYHKD;HH f(x,y) H g(X,y) HenpephIBHbI (H f(x,y) ~ g(X,y)), TO 06'beM9TOm TeJIa paBeH

v = /JU(X,y) -g(x,y))dxdy.

D

4. IIyCTb nOBepXHOCTb 3ap;aHa YPaBHeHHeM Z = f (X, y), (X, y) ED, rp;e <PYHK- D;H:!I f (x, y), a TaK:lKe ee '1aCTHblenpoH3Bop;HbIe nepBoro nOp:!lp;Ka, HenpepbIBHbI B 06JIacTH D. Torp;a ee nJIOIII~ S BbI'IHCJI:!IeTC:!Ino <p0pMYJIe

S= //Jl + f~2(X,y) + f~2(X,y)dxdy.

D

IIpHH:!ITbI TaK:lKe 0603Ha'leHH:!I:f~(x, y) = p, f;(x, y) = q. B TaKOM CJIY'Iae,

S = //..)1 + p2 +q2 dxdy.

D

Bbl,·..tCneHllle cl>1II3I11'"1eCKIIIX III MeXaHIII'"IeCKIIIX Benlll'"llllH

IIpep;noJIO:lKHM, 'ITOIIJIOCKaH nJIacTHHa D HMeeT nOBepXHOCTHYIO IIJIOTHOCTb

pacnpep;eJIeHH:!I Macc p(x,y) HenpepbIBHYIO B D. Torp;a Macca m = m(D) 9TOit nJIacTHHbI BbI'IHCJI:!IeTC:!Ino <popMYJIe

m= //p(x,y)dxdy

D

(<pH3H'IeCKHitCMbICJI ,lI;BoitHoro HHTerpaJIa).

MOMeHTbI HHepD;HH Jx , Jy H Jo nJIOCKoit MaTepHaJIbHoit IIJIacTHHbI D C nOBepxHOCTHOi! IIJIOTHOCTbIO p(x,y) OTHOCHTeJIbHO Koopp;HHaTHbIX oceit Ox, Oy H Ha'laJIa Koopp;HHaT 0(0,0) COOTBeTCTBeHHO BbI'IHCJI:!IIOTC:!Ino <popMYJIaM:

Jx = //y2 p(x,y)dxdy ; J y = //x 2p(x,y)dxdy;

D

 

D

J o = Jx +Jy

= //(x 2 +y2)p(x,y)dxdy.

 

D

 

B CJIY'IaeOP;HOPOP;HOit IIJIacTHHbI (p = 1) 9TH <P0PMYJIbI npHHHMaIOT 60JIee

npoCToit BHP;:

 

 

Jx = //y2 dXdY , J y =

//x 2 dxdy,

Jo = / /(x 2 + y2) dxdy.

D

D

D

KoopP;HHaTbI D;eHTpa T:!I:lKeCTH MaTepHaJIbHoit nJIaCTHHbI D C nJIOTHOCTbIO p(x,y) BbI'IHCJI:!IIOTC:!Ino <popMYJIaM

Mx

YC=m'

154

me

My = !!xp(x,y)dxdy,

M", = !!yp(X,y)dXdy-

D

D

CTaTH'IeCKHeMOMeHTbI nJIaCTHHbI D OTHOCHTeJIbHO oceit Ox H Oy COOTBeTCTBeHHO, a m - ee Macca.

B CJIy'laeO)J;HOPO)J;HOit nJIacTHHbI COOTBeTCTBeHHO HMeeM:

!!XdXdy

!!ydXdy

D

D

Xc = ----:,-:---

Yc = ----:,-:---

!!dXdy'

!!dXdy

D

D

3.3.1.BbPUlCJIHTh IIJIOrn;a,rr.h <PHrYPhI, OrpaHH'IeHHotiKpHBhIMH y2 = 2x H

y=x.

o MMeeM S =!!dxdy. HanpaBJIeHHe, HJIH nOpH,IIOK, HHTerpHpOBaHH5I BhI-

D

6epeM TaK, KaK YKa3aHo Ha 'IepTe)Ke(pHC. 24).

 

 

 

y

x=y

 

 

 

2

 

 

 

 

o

2

 

 

 

 

Pu.c. 24

CHa'IaJIaonpe,IJ;eJIHM KOOp,IJ;HHaThI TO'IKHA:

{

y2 = 2x

2

= 2x

=> Xl = 0, YI = °H X2 = 2, Y2 = 2.

 

=> X

 

 

y =x,

 

 

 

npOeKlIH5I 06JIacTH D Ha OCh Oy eCTh oTpe30K [0,2]. TaKHM 06Pa30M,

3.3.2. BhI'IHCJIHThnJIOrn;a,rr.h napa60JIH'IeCKOrOcerMeHTa AOB, orpaHH-

'IeHHOrO,IJ;yroti BOA napa60JIhI y = ax2 H OTpe3KOM BA, COe,IJ;H- H5IlOrn;HM TO'IKHB(-1,2) H A(1,2).

155

a £CHO, 'ITOypaBHeHHe IIapa60JIbI HMeeT BH)]; y = 2X2 (y(-l) = y(l) = 2).

<l>Hrypa D, IIJIOm;a)l;b KOTOpoii Ha)l;O BbIqHCJIHTb, OrpaHHqeHa CHH3Y IIapa6oJIoii y = 2x2 , a cBepxy - IIPHMOii Y = 2. CJIe)];OBaTeJIbHO,

3.3.3.

BbIqHCJIHTb IIJIOm;a)l;b IIeTJIH KPHBOii

 

( X2 + y2)2 = 2xy .

 

a2

b2

e2

a nO)]; IIeTJIeii 6y)];eM IIO)];pa3YMeBaTb 06JIacTb, OrpaHHqeHHYIO )];aHHOii KpHBoii H paCIIOJIO)l{eHHYIO B IIepBoii qeTBepTH (x ~ 0, y ~ 0). BOCIIOJIb3yeMcH o606m;eHHbIMH IIOJIHPHbIMH KOOp)];HHaTaMH: x = a . r cos <p, y = b . r sin <po B

TaKOM cJIyqae, HKo6HaH IIpeo6pa30BaHHH paBeH

 

 

ax

ax

 

 

 

 

 

J=

or

o<p

= lac?s<p

 

-ar sin <pI = a. b· r.

 

 

 

 

oy

oy

bsm<p

 

brcos<p

 

 

 

 

 

 

 

or

o<p

 

 

 

 

KPHBaH B IIOJIHPHbIX KOOp)];HHaTaX HMeeT BH)];

 

 

2

2

 

2 . 2)2

=

2abr2 sin <pcos <p

'

 

( rcos<p+rsm<p

2

T. e. (r2)2 =

abr2 . 2 sin <p cos <p

 

...;ab .

 

 

2

 

' oTKy)];a r

= -e-y'sm2<p. BHYTpeHHocTb IIe-

e

TJIH, T. e. 06JIaCTb HHTerpHpoBaHHH D B IIpHMoyrOJIbHbIX KOOp)];HHaTaX, 3a-

)];aeTCHHepaBeHCTBOM

 

 

 

 

(

X2

y2)2

2xy

a

2

2

~

 

 

+ b

B IIOJIHPHbIX KOOp)l;HHaTaX COOTBeTcTByIOm;aH 06JIacTb HHTerpHpOBaHHH G

OIIpe)];eJIHeTCH HepaBeHCTBOM 0 ~ r

~ ~y'sin2<p, IIpH 9TOM sin 2<p ~ 0, T. e.

o~ <p ~ ~. TaKHM 06Pa30M,

 

 

 

 

 

s = II dxdy = II abrdrd<p =

 

 

 

 

D

G

Vab =

 

 

 

 

 

11"

11"

 

Vab

 

 

-

-ySlD2cp

-

 

 

 

2

c

I

 

2

(21-oVSID2CP)

 

 

= ab I d<p

 

r dr = ab I d<p

r2 0 c

 

 

o

 

0

 

0

 

 

 

 

 

 

11"

 

 

 

11"

 

 

 

 

"2

2

2

"2

2

 

 

= at I

~~sin 2<pd<p = ~;

I sin 2<p d<p = (~~)

. •

 

 

 

o

 

 

 

0

 

156

B'bt"tuc.!tum'b n.!tow,aau rjjuzyp, ozpa'Hu"te'H'H'btX ?CPU6'btMU:

3.3.4.x = 0, y = ~X, Y = 4 - (x - 1)2.

3.3.5.xy = 4, x + y - 5 = O.

3.3.6. ..;x + fY.... = Va, x + y = a.

3.3.7.x 2 +y = ax, y2 = 2ax, x = 2a, y ~ O.

3.3.8.y2 = lOx + 25, y2 = -6x + 9.

3.3.9.x 2 + y2 = 2x, x 2 + y2 = 4x, Y = x, Y = O.

3.3.10.(x 2 + y2) = 2ax3 , a > O.

3.3.11.x 2 + y2 + 2y = 0, Y = -1, Y = -x.

3.3.12.BbI'UfCJUlTbIIJIOrn;a,n;b qmrYPbI, OrpaHHqeHHoil: KPHBOil:

(4x - 7y + 8)2 + (3x + 8y - 9)2 = 64.

a BbIQHCJIeHH5I IIO <p0pMYJIe

s = II dxdy

D

HeIIpHeMJIeMbI BBH.n:y CJIO)l{HOCTH IIpe,n;eJIOB HHTerpHpOBaHH5I. llpoH3Be,n;eM 3aMeHY IIepeMeHHblx IIO <p0pMYJIaM

 

 

 

 

 

 

1

 

{ 4X -7y + 8 = u

 

 

X = 53 (8u + 7v + 1)

 

{

 

 

 

3x + 8y -

9 = v,

 

 

Y =

l3 (-3u + 4v + 60).

 

 

 

 

 

ax 8

ax

7

ay

3

ay

=

4

TIPH 3TOM au = 53'

av

= 53'au

= -53'

av

53' T.e.

 

 

ax

ax

8

 

7

 

 

 

au

av

53

 

53

1

 

J =

ay

ay

3

4

53 .

 

 

au

8v

53

53

 

B IIJIOCKOCTH Koop,n;HHaT (u, v) COOTBeTCTBYIOrn;M JIHHH5I HMeeT BH,n; u 2 +v 2 =

== 64, T. e IIpe,n;CTaBJI5IeT co6oil: OKPY)I{HOCTb, a 06JIacTb G - Kpyr u2 +v2 ~ 64

C IIJIOrn;a,n;bIO S(G) = 641r.

MCIIOJIb3Y5I COOTBeTcTByIOrn;He <P0PMYJIbI,

IIOJIY-

'laeM

S = II dxdy = II J dudv = II 53 dudv = 53 S (G) = 6:;.

 

 

 

 

 

 

 

1

1

 

 

D

G

 

 

G

 

 

3.3.13.

(x + y - 1)2

(x - Y + 3)2

 

 

4

+

9

 

=1.

 

 

3.3.14.

(2x + 3y - 5)2

(3x -

2y + 1)2

 

 

16

+

 

25

= 1.

 

 

 

 

 

 

3.3.15. BblQHCJIHTb IIJIOrn;a,n;b <PHrYPbI, OrpaHHQeHHoil: KpHBbIMH

 

 

r = a(1 + COSip),

r

= a COS ip,

(a> 0).

 

157

2a

Puc. 25

a JIHBlBr )];aHbI B nomlpHbIX KOOp)];HHaTax, n09TOMY BOCnOJIb3yeMC5I <pOp-

MYJIoA nJIOIIIaAH B nOJI5IpHbIX KOOp)];HHaTax

8 = IIrdrd<p.

G

llepBM <PYHKIJ;H5I r

= a(1 + cos <p) onpe)];eJIeHa npH <p E [-71", 71"1, a BT0-

pM r = a cos <p -

npH <p E [- ~, ~], TaK KaK npH npOqHX 3HaQeHH5IX <p

nOJIYQaeTC5I r < O.

COOTBeTCTBYIOIIIM 06JIacTb HMeeT BH)];, H306p8JKeHHbIA

Ha pHC. 25. BBH)l;y CHMMeTpHH <PHrYPbI OTHOCHTeJIbHO nOJI5IpHoti OCH MO)l{- HO OrpaHHQHTbC5I BbIQHCJIeHHeM nOJIOBHHbI nJIOIIIaAH, a pe3YJIbTaT Y)];BOHTb. lIMeeM

11"

a{l+cos<p)

 

a{l+cos <p)

8=2 I"2

11"

d<p

I

rdr + 2

I d<p

I

rdr =

o

acos <p

 

11"

o

 

 

 

 

 

"2

 

 

 

 

11"

 

 

 

 

 

 

"2

 

 

11"

 

 

= a2

I (1 + 2 cos <p) d<p + a2 1(1 + 2 cos <p + cos2 <p) d<p =

 

 

o

 

 

11"

 

 

 

 

 

 

"2

 

= a' [1(1 + 2 cos,,) d<p +1(1+ 200',,) d<p +1cos' "d,,]

 

 

 

 

2

 

2

 

 

= a' [i(1 + 2=,,) d<p +1(1+ ,;"2,,) d<p] = ~~a'.

 

 

 

 

 

 

2

B'bI."tuc.lI:um'b n.l/,O'l4aaU rjjueyp, oepa'Hu"te'H'H'bI.X "'PU6'b1.MU:

3.3.16.(x42 + y:) 2 = x; _Y:.

3.3.17.(y - X)2 + x 2 = 1.

3.3.18.x 3 + y3 = 2xy, x ~ 0, y ~ O.

158

3.3.19. x 2 + y2 = 2ax, x 2 + y2 = 2bx, y = 0, y = x, 0 < a < b. x 2 y2

3.3.20.a2 + b2 = 1.

3.3.21.xy = a2, xy = b2, Y = m, Y = n (a> b; m > n).

3.3.22.BbI9HCJIHTb 06'beMTeJIa, orpaHHgeHHoro nOBepxHocTflMH y = y'x,

y = 2y'x, x + z = 4, Z = o.

o IIepBble ,n;Ba ypaBHeHHfI H306prur<aroT napa60JIHgeCKHe IJ;HJIHH,n;PbI C BepTHKaJIbHOti o6pa3yrorn;eti, TpeTbe,T. e. x + Z = 4 - ypaBHeHHe HaKJIOHHOti nJIOCKOCTH, a ypaBHeHHe z = 0 - nJIOCKOCTb Oxy. CooTBeTcTByrorn;ee TeJIO H306prur<eHo Ha pHC. 26; cBepxy ero orpaHH9HBaeT nOBepXHOCTb Z = 4 - x.

z

y

 

 

 

 

4

x

 

 

Puc. 26

Puc. 27

 

 

 

06'beMTeJIa BbI9HCJIHM no <p0pMYJIe

 

 

 

 

 

 

V = / / (4 - x) dxdy,

 

 

 

 

 

 

D

 

 

 

 

r,n;e 06JIaCTb D H306prur<eHa Ha pHC. 27. IIMeeM

 

 

 

 

V = /(4

2,rz

2,rz

 

 

 

 

-x) dx / dy =

/(4 -x) dXYI,rzx =

 

 

 

 

o

,rz

0

 

 

 

 

 

 

4

~x~) 14 = 128

 

= /(4 - x)v'x dx = (4. ~x~ _

 

 

o

5

0

15·

 

 

3

 

3.3.23.

BbI9HCJIHTb 06'beMTeJIa, orpaHHgeHHoro nOBepXHOCTflMH Z = 0,

Z = 2 - y, y = x 2

Q TeJIo, 06'beMKOToporo Hy:>KHO BbI9HCJIHTb, H306prur<eHo Ha pHC. 28. B CHJIy cHMMeTpHH TeJIa (KJIHHa) OTHOCHTeJIbHO nJIOCKOCTH Oyz, BbI9HCJIHM 06'b-

eM nOJIOBHHbI TeJIa H pe3YJIbTaT y,n;BOHM. Koop,n;HHaTbI T0geK A H B y,n;OBJIeTBOPflroT CHCTeMe ypaBHeHHti y = x 2 H Y = 2, oTKy,n;a A(J2, 2), B(-J2,2).

159