1-1/2)+(1/2-1/3)+(1/3-1/4).(1/2009-1/2010) = 1-1/2+1/2-1/3+1/3-1/4.1/2009-1/2010答案=2009/2010
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1-1/2)+(1/2-1/3)+(1/3-1/4).(1/2009-1/2010) = 1-1/2+1/2-1/3+1/3-1/4.1/2009-1/2010答案=2009/2010
1-1/2)+(1/2-1/3)+(1/3-1/4).(1/2009-1/2010) = 1-1/2+1/2-1/3+1/3-1/4.1/2009-1/2010
答案=2009/2010
1-1/2)+(1/2-1/3)+(1/3-1/4).(1/2009-1/2010) = 1-1/2+1/2-1/3+1/3-1/4.1/2009-1/2010答案=2009/2010
你写的这一步是去括号
然后-1/2+1/2抵消
-1/3+1/3抵消
……
-1/2009+1/2009抵消
所以=1-1/2010=2009/2010
这应该是某个题目的中间过程吧
比如 让你算数列bn=1/n(n+1)从1到2009的和
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(1-1/2^2)(1-1/3^2)K(1-1/10^2)
(1-1/2^2)(1-1/3^2)K(1-1/10^2)
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(1/2014-1)(1/2013-1)(1-2012-1)...(1/3-1)(1/2-1)
2000*(1-1/2*)*(1-1/3)*...*(1-1999)*(1-1/2000)
计算:(-1)-[1-(1-1/2*1/3)]*6
计算!(-1)-[1-(1-1/2*1/3)]*6
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(1/2+1/3+...+1/2007)*(1+1/2+1/3+...+1/2006)-(1+1/2+1/3+...+/2007)*(1/2+1/3+...+1/2006)
计算:(1/2+1/3+...+1/2011)*(1+1/2+1/3+...+1/2010)-(1+1/2+1/3+...+1/2011)*(1/2+1/3+...+1/2010)
计算(1-1/2-1/3-...-1/2010)*(1/2+1/3+..+1/2011)-(1-1/2-1/3-...-1/2011)*(1/2+1/3+...+1/2010)
2000*(1-1/2)*(1-1/3)*.*(1-1/1999)*(1-1/2000)
(1-1/2004)(1-2003)(1-2002)…(1-1/3)(1-1/2)
(1-1/2)(1-1/3)(1-1/4).(1-1/100)
(1/1+2)+(1/1+2+3)+…+(1/1+2+3…+2000)
(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*...(1+1/2006)*(1-1/2006)怎么简算呀?