Problem

Problem

Statement I For any △ABC\triangle ABC sin⁡(A+B+C3)≥sin⁡A+sin⁡B+sin⁡C3\sin\left(\frac{A+B+C}{3}\right) \ge \frac{\sin A + \sin B + \sin C}{3} Statement II y=sin⁡xy = \sin x is concave downward for x∈(0,π]x \in (0, \pi] .

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