※ 引述《zx153w (oWWWWWWWWWWWo)》之銘言:
: http://i.imgur.com/6MEHc3d.jpg
: 想很久…但沒什麼想法
: 想不到要怎麼起手破解
DE = a
AE = b
CD = h
△CDE = △AEF = △FBC
AF = ah/b
FB = ah/(a + b)
AF + FB = CD
=> [a/b + a/(a + b)]h = h
令x = b/a
=> 1/x + 1/(1 + x) = 1
=> 1 + 2x = x^2 + x
=> x = (1/2)[1 + √5]
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 61.56.10.112
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1500616667.A.F42.html