(1)
BE的斜率(p - 0)/(0 - b) = -p/b
AC斜率(a - 0)/(0 - c) = -a/c
BE⊥AC, (-p/b)(-a/c) = pa/(bc) = -1 (i)
CF的斜率u = (p - 0)/(0 - c) = -p/c
AB斜率 v = (a - 0)/(0 - b) = -a/b
uv = (-p/c)(-a/b) = pa/(bc) = -1
CF⊥AB
(2)
O, E分别是BC、AC的中点:
b + c = 0, c = -b (ii)
E(c/2, a/2)
BE的方程: (y - 0)/(a/2 - 0) = (x - b)/(c/2 - b), y = a(b - x)/(3b) (用ii)
x = 0, y = p = a/3
CF的方程: x/c + y/(a/3) = 1 (iii)
AB的方程: x/b + y/a = 1 (iv)
由(iii)(iv): F(b/2, a/2), F是AB的中点
内容全部来源于网络收集，如有侵权，请联系网站删除：QQ：24596024