修正一下！

来源: 于 2026-04-30 12:38:31 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

ab=21

h=28/a

h/a=(2b-(b/a)x)/x

S=bx=2(ab)^2/49=18

Note S is independent of the value either a or b takes, given ab is constant. Mathematically, it is valid to set a=b to facilitate the evaluation:)))