计算,1/2x4+1/4x6+1/6x8+.+1/ - 知识问答

计算,1/2x4+1/4x6+1/6x8+.+1/48x50=?,1/2+1/6+1/12+1/20+1/30+1/42

2个回答

计算,
1/2x4+1/4x6+1/6x8+.+1/48x50
=1/2×（1/2-1/4+1/4-1/6+1/6-1/8+……+1/48-1/50）
=1/2×（1/2-1/50）
=1/2×12/25
=6/25,
1/2+1/6+1/12+1/20+1/30+1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7

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