二重积分练习题 下载本文

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二重积分自测题 (一)选择题

1.设D是由直线x?0,y?0,x?y?3,x?y?5所围成的闭区域, 记:I1???ln(x?y)d?,ID2???ln2(x?y)d?,则( )

D A.I1?I2 B.I1?I2 C.I2?2I1 D.无法比较 2.设D是由x轴和y?sinx(x?[0,?])所围成,则积分 A.

??yd??( )

D???? B. C. D. 64322 3.设积分区域D由y?x和y?x?2围成,则??f(x,y)d??( )

D A. C.

?2?1dx?2f(x,y)dy B.?dx?f(x,y)dy

x?10x?222?1?2dx?2f(x,y)dy D.?dx?2f(x,y)dy

x0xx?21x?2 4.设f(x,y)是连续函数,则累次积分 A.

?404dx?2xxf(x,y)dy?( )

f(x,y)dx

?dy?04y12y4f(x,y)dx B.?dy?012y4?y C.

?40dy?1f(x,y)dx D.?dy?140y4yy2f(x,y)dx

2 5.累次积分 A.

?20dx?e?ydy?( )

x221111(1?e?2) B.(1?e?4) C.(1?e?4) D.(1?e?2) 23231122226.设D由?x?y?1确定,若I1???2,d?I?(x?y)d?, 22??4Dx?yDI3???ln(x2?y2)d?,则I1,I2,I3之间的大小顺序为( )

D A.I1?I2?I3 B.I1?I3?I2 C.I2?I3?I1 D.I3?I2?I1

7.设D由|x|?1,|y|?1确定,则

cosxyxesinxydxdy?( ) ??D A.0 B.e C.2 D.e?2

8.若积分区域D由x?y?1,x?0,y?0确定,且

?10f(x)dx??xf(x)dx,

x1??f(x)dxdy?( )

D 2

A.2 B.0 C. 9.若

1 D.1 21x2(y)0x1(y)?0?1dx?1?x0f(x,y)dy??dx?011?x0f(x,y)dy??dy?f(x,y)dx,则( )

A.x1(y)?y?1,x2(y)?0 B.x1(y)?y?1,x2(y)?1?y C.x1(y)?1?y,x2(y)?y?1 D.x1(y)?0,x2(y)?y?1

(二)填空题

1.设D是由直线y?x,y?1x,y?2所围成的区域,则??dxdy? . 2D 2.已知D是由a?x?b,0?y?1所围成的区域,且

??yf(x)dxdy?1,则

D1?baf(x)dx? .

3.若D是由x?y?1和两坐标轴围成的区域,且

??Df(x)dxdy???(x)dx,那么

0?(x)? .

4.交换积分次序:

?2?1dy?2f(x,y)dx? .

yy?2x2?y2?1确定,则??dxdy? . 5.设D由4D 6.交换积分次序: 7.交换积分次序: 8. 交换积分次序

?2?0dx?sinx0f(x,y)dy? .

?dx?0y21xx2f(x,y)dy= .

?dy?02yf(x,y)dx= .

(三)计算题

1.选择适当的坐标系和积分次序求下列二重积分 (1)

(2)(3)(4)

3

2??xcosydxdy, 其中D由1?x?2,0?y?D22D, 其中由x?y?2x确定, (x?y)dxdy???确定, 2D??Dx2?y2dxdy,其中D是圆环形闭区域:1?x2?y2?4 xydxdy,其中D是由抛物线y?x及y=x所围成的闭区域.

2??D

2.计算下列积分 (1)

??60dy?dy??6ycosxdx, x (2)

?331y1dx, ylnx 4