1²-2²+3²-4²+.+99²-100²+101²
=101²-100²+...+3²-2²+1²
=(101+100)(101-100)+(99+98)(99-98)+...+(3+2)(3-2)+1
=201+197+...+5+1
=(201+1)×51÷2
=5151
1²-2²+3²-4²+.+99²-10²=101² 计算
1²-2²+3²-4²+.+99²-10²=101² 计算
1²-2²+3²-4²+......+99²-100²+101² 计算
1²-2²+3²-4²+......+99²-100²+101² 计算
数学人气:816 ℃时间:2020-01-27 20:58:28
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