結果這麽clean啊！怎麽推倒出來的？

所有跟帖： 

• 哦，原始推導居然用了曲麵積分。 -貧論員- ♀ (19 bytes) () 08/15/2011 postreply 12:09:26

• 不是曲麵積分。是積分求旋轉麵. -jinjing- ♀ (203 bytes) () 08/15/2011 postreply 16:26:28

• 死算出來的。一直沒想出純幾何方法求h -wxcfan123- ♂ (219 bytes) () 08/15/2011 postreply 14:39:14

• You Rit. We also can use similar tringles and ...getting h(r-h)= -jinjing- ♀ (0 bytes) () 08/15/2011 postreply 16:44:33

• (R+r-h)^2=(R+r)^2-R^2-h^2,... -jinjing- ♀ (0 bytes) () 08/15/2011 postreply 17:31:02

• Sorry, It should be: (R+r-h)h=(R+r)^2-R^2-h^2,... -jinjing- ♀ (0 bytes) () 08/15/2011 postreply 17:33:49