1/1×3+1/2×4+…1/2008×2010+1/2009×2011的结果
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1/1×3+1/2×4+…1/2008×2010+1/2009×2011的结果
1/1×3+1/2×4+…1/2008×2010+1/2009×2011的结果
1/1×3+1/2×4+…1/2008×2010+1/2009×2011的结果
1/1×3+1/2×4+…1/2008×2010+1/2009×2011
=(1/2)×(1-1/3)+(1/2)×(1/2-1/4)+.+(1/2)(1/2008-1/2010)+(1/2)(1/2009-1/2011)
=(1/2)(1-1/3+1/3-1/5+1/5-.-1/2009+1/2009-1/2011)+(1/2)(1/2-1/4+.-1/2008
+1/2008- 1/2010)
=(1/2)×(1-1/2011)+(1/2)×(1/2-1/2010)
=(1/2)×(1+1/2-1/2011-1/2010)
=(1/2)×(6059144/4042110)
=1514786/2021055
1/1×3+1/2×4+…1/2008×2010+1/2009×2011
=(1/2)×(1-1/3)+(1/2)×(1/2-1/4)+............+(1/2)(1/2008-1/2010)+(1/2)(1/2009-1/2011)
=(1/2)(1-1/3+1/3-1/5+1/5-.......-1/2009+1/2009-1/2011)+(1/2)(...
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1/1×3+1/2×4+…1/2008×2010+1/2009×2011
=(1/2)×(1-1/3)+(1/2)×(1/2-1/4)+............+(1/2)(1/2008-1/2010)+(1/2)(1/2009-1/2011)
=(1/2)(1-1/3+1/3-1/5+1/5-.......-1/2009+1/2009-1/2011)+(1/2)(1/2-1/4+.......-1/2008+1/2008-1/2010)
=(1/2)×(1-1/2011)+(1/2)×(1/2-1/2010)
=(1/2)×(1+1/2-1/2011-1/2010)
=(1/2)×(6059144/4042110)
=1514786/2021055
脚都打酸了。。。这么多。。为了练习打字。。照楼上的再打一遍。。花了我半个小时。。郁闷。。这么多。。
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