Recent content by ER901

  1. E

    Lengths of line secgment that bisect angle

    Homework Statement Let t_i be the lengths of the line segments that bisect angle Ai of a triangle. The segments go from A_i to the opposite side. Let a_i be the lengths of the sides opposite angle A_i. Prove the following inequalities: \sumfrom i=1to 3 1/t_{}i > \sum from i=1 to 3...
  2. E

    Proving Triangle Angles Equation: cos^2 A + cos^2 B + cos^2 C + 2*cosA*cosB*cosC

    Homework Statement I need to prove the following equation: cos^2 A + cos^2 B + cos^2 C + 2*cosA*cosB*cosC = 1 where A,B,C are the angles of a triangle Homework Equations A+B+C = 180 The Attempt at a Solution I substituted the sum of A,B,C into the equation, and now I have something...