Whats the length of the angle bisector AM of the triangle ABC, if AB = c,

AC = b and ∠A = α

1 answer

AM^2 = bc [1 − (a^2/(b + c)^2)]

see

geometry-math-journal.ro/pdf/Volume1-Issue1/ON%20THE%20STANDARD%20LENGTHS%20OF%20ANGLE%20BISECTORS%20AND%20THE%20ANGLE%20BISECTOR%20THEOREM.pdf

or

proofwiki.org/wiki/Length_of_Angle_Bisector