MathDB
India TST:Day2 Problem 1

Source: easy

May 16, 2009
geometrycircumcircletrigonometrygeometry proposed

Problem Statement

Let γ \gamma be circumcircle of △ABC \triangle ABC.Let Ra R_a be radius of circle touching AB,AC AB,AC&γ \gamma internally.Define Rb,Rc R_b,R_c similarly. Prove That \frac {1}{aR_a} \plus{} \frac {1}{bR_b} \plus{} \frac {1}{cR_c} \equal{} \frac {s^2}{rabc}.
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