In △ ABC, point D is the intersection of bisector of ∠ C and base ab. the following inequality is proved: CD & # 178; = AC · BC-AD · BD

In △ ABC, point D is the intersection of bisector of ∠ C and base ab. the following inequality is proved: CD & # 178; = AC · BC-AD · BD

In △ ABC, point D is the intersection of bisector of ∠ C and base ab. the following equation is proved: CD & # 178; = AC · BC-AD · BD. it can be proved by sine theorem: let x = 1 / 2 ∠ c y = ∠ ADC, CD / Sina = ad / SiNx = AC / siny = UCD = u Sina = u sin (x + y) ad = u sin XAC