1/3×5+1/5×7+1/7×9+…+1/99×100

题目详情

1/3×5 +1/5×7 + 1/7×9 + …+ 1/99×100

▼优质解答

答案和解析

1/3×5 +1/5×7 + 1/7×9 + …+ 1/99×101
=1/2×(1/3-1/5)+1/2×(1/5-1/7)+……+1/2×(1/99-1/101)
=1/2×(1/3-1/5+1/5-1/7……1/99-1/101)
=1/2×(1/3-1/101)
=49/303

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