⑩天掌 Teaching Plan on Advanced Mathematics 又如球面x2+y2+z2=a2可看成xO面上的半圆周 x=asin p, y=0, 0≤q≤丌 Z=acos P 绕轴旋转所得(图7-49),故球面方程为 「x= asin cos 6, 0≤q≤丌 y= sinsin0,0≤<2元 =acoS卯 图7-49 返回 tianjin polytechnic dmivendityTianjin Polytechnic University Teaching Plan on Advanced Mathematics 又如球面 2 2 2 2 x + y + z = a 可看成zOx面上的半圆周      = = =   cos 0, sin , z a y x a 0     绕z轴旋转所得(图7-49), 故球面方程为      = = = cos . sin sin , sin cos ,      z a y a x a     0 2 0     图7-49 x y z O 返回