已知α,β,γ是有理数,且α＋β＋γ＝0,则α²＋β²＋γ²‐βγ‐γα‐αβ＝（ ）
人气：479 ℃ 时间：2020-01-01 04:39:53
解答
α²＋β²＋γ²‐βγ‐γα‐αβ＝1/2×2（α²＋β²＋γ²‐βγ‐γα‐αβ）＝1/2×（α²＋β²＋γ²＋α²＋β²＋γ²‐2βγ‐2γα‐2αβ）＝1/2...
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