文档内容
2025
专项刷题班
-第六章
二重积分n n n
例6.1 lim ( 1 7 ).
n n i n2 j2
i1 j1
1 1
1 x 1 x
(A) dx dy (B) dx dy
0 0 1 x 1 y2 0 0 1 x 1 y
1 1
1 1 1 1
(C) dx dy (D) dx dy
0 0 1 x 1 y 0 0 1 x 1 y2
N
I
Im
=
(H)(H)n
M
=
vexity
to (ax)
Is vx yay ay
= ax =1
例6.2 设D由 x 0, y 0, x y , x y 1围成,且
2
I ln3( x y)dxdy,I ( x y)3dxdy,I [1 cos(x y)]3dxdy,
1 2 3
D D D
其中,则I , I , I 之间的大小顺序为( C )
1 2 3
(A)I I I (B)I I I (C)I I I (D)I I I
1 2 3 3 2 1 1 3 2 3 1 2
↓ Y Estel B ** Int Ed "
t X+ t 1-cost
=
, ,
, , ,
X+y
=
/
: t: 1 : In t = 0 EO Most O
. D
,
X+ y z
=
Int
S
:
↑ fitt (1 flol
= +- - cost) = t - I + cost = o
,
fitl 1-Sm+> 0 : fit) : f(t) fio)
O
= > =
: to Most , 1 < Is < 12
.例6.3 设l : x2 y2 1,l : x2 y2 2,l : x2 2 y2 2,l : 2x2 y2 2,为
1 2 3 4
y2
四条封闭曲线,记I (1 x2 )dxdy(i 1,2,3,4),则
i
2
D
i
max{I , I , I , I } ( ).
1 2 3 4
(A)I (B)I (C)I (D)
1 2 3
I
4
X
1)
)
1
:
= .
Bil
: iR fo ED C D2
, , ,
↓ fixyl I fixy
no
= as
1- X - 30X
# = (D)
+DulA fIxy)30 ED CD+ : 2 <14
: ,
.
fiya
I fixy) not
In
=
10
far 11 fia
# Is I
+
=
, H
D4 -
F
:
DE fixy) TE* fix d
Eit 0 *
:
,
000
1) Adxay
:
D
例6.4 设 f x, y 为连续函数,则使
2
2 4x
f (x, y)dxdy 4 dx f x, y dy成立的一个充分条件是( D ).
0 0 .
2 2
x y 4
( X A) f x, y f x, y D = g ↑
X
(B) f x, y f x, y 且 f x, y f x, y
=8 'I/1
X (C) f x, y f x, y
,
&
2
(D) f x, y f x, y 且 f x, y f x, y - 2例6.5 设区域D {(x, y) || x | | y | 1},则二重积分
I (1 x)(1 y)(1 x y )dxdy =_______.
↑
D
X
2 = () (1 - x - y +xy) (1 - 1) - 191)dxay 11 Y = 1 1= X
!x(
! (1 ( 11) axay 1x) MI)axay
- - - - -
=
+
-11 y(-M-Bildxay xy (l-x-1d
4()ux) 5
4x5
4b(1 -X - y)axay = ( -x - y(xy = =
=例6.6 极坐标系(,)中的累次积分
1
I 2 d f (cos,sin)d可化为直角坐标系(x, y)中的累次
1
0
cossin
积分 ( B ).
2 2 f (x, y)
1 1x 1 1x
(A) dx f (x, y)dy (B) dx dy
0 1x 0 1x x2 y2
2 2 f (x, y)
1 1x 1 1x
(C) dx f (x, y)dy (D) dx dy
0 x 0 x x2 y2
ootsm o xy
↑
X+ Y
=
1 P=
=
,
⑪
= ' fro psmo
73
,
=
-
xay
a1
例6.7 设函数 f (x)在区间[0,1]上连续,并设 f (x)dx A,求
0
1 1
dx f (x) f ( y)dy.
Y =1
N
0 x
Day
1, 11 fix-fly)
10 fillay
75 fina axy x
= . =
&
"
Cay) fix figiux /fig) my ? fixax (X) X=
· =
=
!
= fix flyoxay 11 f(x) =
faxay ff
TB yi
=
fillay 1 fixux =
↓ !
=
·
·1
例6.7 设函数 f (x)在区间[0,1]上连续,并设 f (x)dx A,求
0
1 1
dx f (x) f ( y)dy.
0 x
( 1. (
f()my xfay
75 ) fax =
35
= = =
)
. fitldt
Fix =t t
例6.8 设 f (x)为连续函数,F(t) dy f ( x)dx,则F(2)等于( B )
1 y
(A)2 f (2) (B) f (2) (C) f (2) (D) 0
N Ct E)
FR 1) fix axay = (ax) fix my , · Y=2
=
XXD
y
=
y
=1
(1)
(
, fix)
= (x+ ) ax S
F(l f(t) f(2)
(t 1)
= + =
.
==2例6.9 设区域D {(x, y) | x2 y2 R2},则二重积分
x2 y2
I ( )dxdy ______.
a2 b2 Y
=X
xx
D
# 4/1 (x 1 ?
1 laxa
: =
FP)
:
33
-
EJBXJFF
13
,
=:
xaxayaxy
4/1 =) *
· I + axay 4(a axay
= = +例6.9 设区域D {(x, y) | x2 y2 R2},则二重积分
x2 y2
I ( )dxdy ______.
a2 b2
D
2(at + b Ex y's axay
) +
=
,
)n01
*
+ p2pdp
Cat
= -
= R +
例6.10 设I max x, y dxdy, I min x, y dxdy,
1 2
D D
I [x y]dxdy其中D {(x, y) | 0 x 1,0 y 1}, a 表示不超过
3
D
a
的最大整数, 则有( D ).
.
(A)I I I (B) I I I (C)I I I (D)I I I
1 2 3 1 2 3 1 3 2 1 3 2
y= X
↑
I
axay yaxay 2
2 /x xaya
=
= uxx
Dr
yax
,
2/jax/xay 3 3
= = 8 I
!yaxay + 2)'ax)
22 x axay 21 y axay yay -
= =
=
=
!
,DA0 : x+ Y = 2 x
,
Ds Dx
0xty < /
0,
I
[x y]
+ = Ds
Do
LEX+y c2
1
3
,
(E) 1y
ven (11)
2 = 2 =1 X
,
blEx+y] axay- oaxa llaxay =
: +
=
x
3
:
2 ] 22.
i x = =
,↑
例6.11 设平面区域D {(x, y) |1 x2 y2 4, x 0. y 0}.计算
xsin( x2 y2 )
X
dxdy.
x y
EN
D
EFE(ER)
15-
:
EFEFE FJ
33
=:
x Sman +yaxd %
= =// . Smay
1 i
Y
x+
2221
mx
y
:
10 P
Esma =
· I xityaxey
=
=2 2 1
a a a x
例6.12 计算I dx dy (a 0).
0 x x2 y2 4a2 x2 y2
Y = a+ a Y > y +a = ax ) X + (4 + ai = a 1
X=a
af a) pE
x y
2ay zaPSmO
= + + + = -
S
I ⑪
axay
To =
**
xty2 -
4
·
S
8
zusmO
id - 1 (a
-a)
.
pap
=
a
·
a
s
(iarism P (cod
=
ao =e(x y), x 0, y 0
例6.13 设 f (x, y) ,求I f (x, y)dxdy,其中
0, 其它
D
D
是由 x y 1, x y 2, y 0和 y 3所围成的闭区域.
&
D2
: 2 11 fixylaxay fixylaxiy x
+
=
"Gile
Py)
,
(x+
-
·
leavy
X+y 2
11/an =
=
y
x+ =1
>
12
leaxayl eay
P
35- 2 0
:
= S
eaxay
-11
1 = Eaxy
35 i
=:
YA
16=
Pax/eay -)ux)
ze e
ay
=
= -=P cosotsmo Du
35 = = x+ y = 1 < po + PSmO = 1 = x 7
x+y
2 Ep
(x+ y))
= =
e
O
cat mo
X+y 2
=
y
/00/o x+ =1
= e-ploso
+ sholp
>
ap
( 2
①
O
S
Co2O+O
= cosonsmo
I
do e-Plosotsmosp
⑮otsma
(cosothold
Cosataq
100+Sma
7) #
Z I
I ~e-t
cosotsmo
- no + at
.
,
·
N
I I
d
no = o
=
Su