SolFeb2605

If a, b, and c are the sides of a nondegenerate triangle then

{{a}\over{c+b}}+{{b}\over{c+a}}+{{c}\over{b+a}}\leq 2

Solution I by Bump

Without loss of generality we can take: a\le b \le c\,.

{{a}\over{c+b}}+{{b}\over{c+a}}+{{c}\over{b+a}}\leq {{a}\over{a+b}}+{{b}\over{a+b}}+{{c}\over{a+b}} =1+{{c}\over{a+b}}\le 2

Since a+b\ge c\, by the triangle inequality.