A Geometric Proof of Blundon’s Inequalities

نویسندگان

  • DORIN ANDRICA
  • CATALIN BARBU
چکیده

A geometric approach of Blundon’s inequality is presented. Theorem 2.1 gives the formula for cos ̂ ION in terms of the symmetric invariants s , R , r of a triangle, implying Blundon’s inequality (Theorem 2.2). A dual formula for cos ̂ IaONa is given in Theorem 3.1 and this implies the dual Blundon’s inequality (Theorem 3.2). As applications, some inequalities involving the exradii of the triangle are presented in the last section. Mathematics subject classification (2010): 26D05; 26D15; 51N35..

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تاریخ انتشار 2012