(x cos a+y cos B+z cos n)ds=zds h dxdy 故所求积分为 (x cos a+y cos B+z cos y)ds =h2-h14=-1mh 2     +  +  = 1 1 2 2 2 2  (x cos y cos z cos )dS z dS  = Dxy h dxdy 2 故所求积分为   (x cos + y cos + z cos )dS 2 2 2 4 2 1 = h 4 − h . 2 1 4 = − h