Question

计算二重积分∫∫D (x+y)dxdy D:y=x,y=2,x=0？

Answer 1

方法辩弊斗如下，携磨
请作参卜枯考：

追答

Answer 2

∫∫(D) (x+y)dxdy
=∫旦链(0,2)dx∫(x,2)(x+y)dy
=∫(0,2)dx*(xy+y^2/隐迟隐灶厅2)|(x,2)
=∫(0,2) (2x+2-x^2-x^2/2)dx
=(x^2+2x-x^3/2)|(0,2)
=4+4-4
=4