Let ABC be a triangle and D the foot of the altitude from A. Let E and F lie on a line passing through D such that AE is perpendicular to BE, AF is perpendicular to CF, and E and F are different from D. Let M and N be the midpoints of the segments BC and EF, respectively. Prove that AN is perpendicular to NM.
I keep accidentally deleting before posting. Here's the extremely short version (all algebra steps omitted.)
Points D,E,F are all on line y=mx
E and F are also points on circles.
Slope AN = -1(2a-mb-mc)/(b+c+2am)
Slope MN = (b+c+2am)/(2a-bm-cm)
If anyone would like me to fill in details later I will.
Posted by Jer
on 2012-12-26 23:49:36