计算二重积分：其中D由直线y=x，y=0，x=π/2所围成。

A . 2/3 B . 4/3 C . 2 D . 8/3

A . A B . B C . C D . D

A . A B . B C . C D . D

A . π ／4 B . π／2 C . π ／4+1 D . π／2+1

A .https://assets.asklib.com/psource/1471495583069031849.png B .https://assets.asklib.com/psource/1471495590625056973.png C .https://assets.asklib.com/psource/1471495595542085890.png D .https://assets.asklib.com/psource/1471495600517057301.png

A .https://assets.asklib.com/psource/2015102914095653127.jpg B .https://assets.asklib.com/psource/2015102914101219015.jpg C .https://assets.asklib.com/psource/2015102914103264282.jpg D .https://assets.asklib.com/psource/2015102914105028342.jpg

A . I≤-36π B . -36π≤I＜36π C . 36π≤I≤100π D . I＞100π

<img src='https://img2.soutiyun.com/ask/2021-01-10/979142709737969.png' />,D是由抛物线y=x²与0x轴和直线x=1围成的区域.(计算二重积分)

A．2/3 B．4/3 C．2 D．8/3

若<img src='https://img2.soutiyun.com/ask/2020-12-21/977393359641804.png' />则积分区域D可以是(). A.由x轴,y轴及x+y-2=0所围成的区域 B.由x=1,r=2及y=2,y=4所围成的区域 C.由|x|=<img src='https://img2.soutiyun.com/ask/2020-12-21/97739339367075.png' />,|y|= 所围成的区域 D.由|r+y|=1,|x-y|=1所围成的区域

计算<img src='https://img2.soutiyun.com/ask/2020-12-15/976873540708041.png' />其中D由y=x,y=1/2x,x=2围成.

计算<img src='https://img2.soutiyun.com/ask/2019-12-11/944947946681969.png' />，其中D为圆周x²+y²=9和x²+y²=1与直线y=x，y=0所围成的第一象限部分

设<img src='https://img2.soutiyun.com/ask/2020-11-25/975176661728809.png' />,其中D₁={(x,y)|-1≤x≤1,-2≤y≤2};又<img src='https://img2.soutiyun.com/ask/2020-11-25/975176672687436.png' />,其中D₂={(x,y)10≤x≤1,0≤y≤2)}.试利用二重积分的几何意义说明I₁与I₂之间的关系.

计算二重积分<img src='https://img2.soutiyun.com/ask/2020-11-16/974405066984158.png' />其中D是由曲线 <img src='https://img2.soutiyun.com/ask/2020-11-16/974405083233088.png' />(a＞0)和直线y=-x所围成的区域.

计算二重积分<img src='https://img2.soutiyun.com/ask/uploadfile/9819001-9822000/7e7e913efe352aafa56c54d501987c2e.png' />，其中积分区域D是由直线x+y=2，y=x及y=0所围成的区域.

A．I≤-36π B． -36π≤I＜36π C． 36π≤I≤100π D． I＞100π

将二重积分<img src='https://img2.soutiyun.com/ask/2021-01-19/979920905720396.png' />按两种次序化为累次积分，积分区域D分别给定如下： (1)D由曲线y=x³与直线y=1，x=-1所围成，如图7-21所示; (2)D由圆x²+y²≤4所围成，如图7-22所示; (3)D由直线y=2x，y=0及x=3所围成，如图7-23所示. <img src='https://img2.soutiyun.com/ask/2021-01-19/97992096192361.png' />

设D是第一象限内由直线y=ax与y=bx(b＞a≥0)构成的角形城.求无界城D上的二重积分: <img src='https://img2.soutiyun.com/ask/2021-01-10/979151084599984.png' />

设积分区城为D=|(x,y)}0≤x≤1,0≤y≤1}.计算二重积分 <img src='https://img2.soutiyun.com/ask/2021-01-10/979148559653565.png' />

计算<img src='https://img2.soutiyun.com/ask/2021-01-02/978464841600073.png' />其中D是由直线y=0;y=1及双曲线x²-y²=1所围成的闭区域