Consider the rectangular region R shown in figure 14.1.9.
Approximate the double integral ∫∫ (x+y) dA using a Riemann sum
R
* *
and the R shown in figure. Choose the sample points(x , y ) at
k k k
(a) the geometric center of each R and
k
(b) the upper left-hand corner of each R
k
y
__________|____________
| | | | |
|R8 | R7 | R6 | R5 |
| | | |
|__ _|_ 1_|___ _|____ |_ figure 14.1.9
| | | | |
| R| | R2 | R3 | R4 |
| | | | |
|____|___ |__ _________|______x
|
1
2.suppose that ∫∫ x dA = 3 , ∫∫ y dA = 7, and the area of R is 8
R R
∫ ∫(3x+7y+1)dA = ?
R
这2题看原文书看不懂,可以麻烦写算式给我参考吗??麻烦了谢谢