高数课程妥媒血课件 镭理工大理>> 解2采用柱面坐标 2 x+y=z→3=f,D:x2+y2≤a g:r≤z≤a,0≤r≤a,0≤θ≤2π, =∫j/x2+y)ohk= 1e o rdr[rdz 2Tr(a-rdr=2r([a 45-10 Http://www.heut.edu.cn解 2 采用柱面坐标 : , 2 2 2 D x + y  a   I = (x + y )dxdydz 2 2     =  a r a d rdr r dz 2 0 2 0  =  − a r a r dr 0 3 2 ( ) ] 4 5 2 [ 4 5 a a =  a  − . 10 5 a  = 2 2 2  x + y = z  z = r,  : r  z  a, 0  r  a, 0    2