two steps or

來源: 於 2010-04-10 06:11:51 [舊帖] [給我悄悄話] 本文已被閱讀：次

B=centre angle in radians
A=1/2*r^2(B-sinB), numerical solution of B then
H=r-rcos(B/2),

or
B=2arccos(1-H/r)

A=1/2*r^2{2arccos(1-H/r)-sin[2arccos(1-H/r)]}