1×1+2×2+3×3+······+2007×2007+2008×2008+2009×2009=?
来源:百度知道 编辑:UC知道 时间:2024/06/25 04:47:57
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俺是小学生!请用小学奥术能理解的方式回答 ,我算出8064121
俺是小学生!请用小学奥术能理解的方式回答 ,我算出8064121
1×1+2×2+3×3+······+2007×2007+2008×2008+2009×2009
=2009×(2009+1)×(2009×2+1)/6
=2704847285
1²+2²+3²…+n²=1/6n(n+1)(2n+1)=2704847285
..可怜我的计算器...
实在看不懂这有解答
http://i.cn.yahoo.com/qianhuacn2002/blog/p_196/
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