Question 401255
The best way to fully understand (and memorize) a theorem is to try to derive it or prove it.


Take Stewart's theorem for example. Consider a triangle ABC that has a cevian extending from A onto segment BC, intersecting BC at point D. Stewart's theorem says that:


{{{(AB^2)(DC) + (AC^2)(BC) = (BC)(AD + (BD*DC))}}}


Can you prove it?