|1-1/2|+|1/2-1/3|+|1/3-1/4|+|14/-+···+|1/2012-1/2013|+|1/201
|1-1/2|+|1/2-1/3|+|1/3-1/4|+|14/-+···+|1/2012-1/2013|+|1/201
计算(1-1/2²)(1-1/3²)(1-1/4²)×···×(1-1/2013²
计算 1*2/1+2*3/1+3*4/1+············+2009*2010/1
1/2+1/2+3+1/2+3+4+···+1/2+3+4+···+200
(100+99-98-97+···+4+3-2-1)*(2012*2013-1)分之(2012+2011*2013)
数列 1/2,3/2,1/3 ,4/3,·········1/n+1,n+2/n+1,·········是否有极限?
1,1+2,1+2+3,1+2+3+4,······,第几项等于120
-1*1/2+(-1/2*1/3)+(-1/3*1/4)+···+(-1/2010*1/2011)
计算(1-1/2)* (1-1/3)*(1-1/4)*······(1-1/2006)*(1-1/2007)
n*(n+1)分之1等于【 】N为正整数,利用规律算1*2分之1+2*3分之1+3*4分之1·····=2012*201
(2012分之1-1)×(2011分之1-1)×(2010分之1-1)···(4分之1-1)×(3分之1-1)×(2分之
1*2*3···2008*2009*(-1)*(-1/2)*(-1/3)···(-1/2008)*(1/2009)