# OEF 二重积分 --- 介绍 ---

### 二重积分 I

 D = dx

(填充各种情况.)
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### 二重积分 II

D

.

xrange , yrange , linewidth=2 fpoly skyblue,,,,,,, poly blue,,,,,,, text black,,giant,A text black,,giant,B text black,,giant,C text black,,giant,D text black,,giant,E text black,,giant,F linewidth 1 vline 0,0, black hline 0,0, black parallel ,,,, 0,1, 20, grey parallel ,,,, 1,0, 20, grey arrow 0,, 0,,10,black arrow ,0, ,0 ,10,black

### 二重积分 III

D

. 问缺少的积分限是什么 ?

xrange , yrange , linewidth=2 fpoly skyblue,,,,,,, poly blue,,,,,,, text black,,giant,A text black,,giant,B text black,,giant,C text black,,giant,D text black,,giant,E text black,,giant,F linewidth 1 hline 0,0, black hline 0,0 , black parallel ,,,, 0,1, 20, grey parallel ,,,, 1,0, 20, grey arrow 0,, 0,,10,black arrow ,0, ,0 ,10,black

### 二重积分 IV

 设 , , , , , 是平面的点, 是多边形 围成的区域 (见图). 可以把二重积分 D 写成公式 1 . 或公式 2 其中 是实数. 你选择哪一个 (1 或 2)? 积分限是什么 ? xrange , yrange , linewidth=2 fpoly skyblue,,,,,,, poly blue,,,,,,, text black,,giant,A text black,,giant,B text black,,giant,C text black,,giant,D text black,,giant,E text black,,giant,F linewidth 1 hline 0,0, black hline 0,0 , black parallel ,,,, 0,1, 20, grey parallel ,,,, 1,0, 20, grey arrow 0,, 0,,10,black arrow ,0, ,0 ,10,black