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计算1/1×3+1/3×5+1/5×7+1/7×9+1/9×11+.1/49×51

题目详情
计算 1/1×3+1/3×5+1/5×7+1/7×9+1/9×11+.1/49×51
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答案和解析
1/1×3+1/3×5+1/5×7+1/7×9+1/9×11+.1/49×51
=1/2×(1-1/3)+1/2×(1/3-1/5)+1/2×(1/5-1/7)+.+1/2×(1/49-1/51)
=1/2×(1-1/3+1/3-1/5+1/5-1/7+...+1/49-1/51)
=1/2×(1-1/51)
=1/2×50/51
=25/51;
新问题请重新发帖提问,这里不再回答谢谢
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