In triangle ABC, BC=8. The length of median AD is 5. Let M be the largest possible value of AB^2+AC^2, and let m be the smallest possible value. Find M-m.
AB2=25+16−40cos(180−θ)AB2=41+40cosθAC2=41−40cosθAB2+AC2=82M=m=82M−m=0
+47 
