Every Point on the Bisector of an Angle Is Equidistant from the Sides of the Angle.
In a ABC, t...
Question
In a △ABC, the lengths of the bisectors of the angle A,B and C are x,y,z respectively. Show that 1xcosA2+1ycosB2+1zcosC2=1a+1b+1c. Also show that ab+c=√1−x2bc