1/2+1/6+1/12+······+1/9900埃及分数怎样算

急·····················1+2+3+...+999=? 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 简算 1/2+1/6+1/12+······+1/9900 纸鹤数量的意义比如说 1只纸鹤,代表······· 2只纸鹤,代表······· ······················· ···························· ·················· 越多越好, 变态数学题·······方程一道············x+2y+3z=1x=y+12x+3y+5z=2方程组············要过程············我解了之后总觉得无解····· 俗语和名句的填空1······,自知之明.2······,行必果.3工欲善其事,······.4临渊羡鱼,······.5非学无以广才,······.6······,福兮祸之所伏.7项庄舞剑,······.8······,人以群 计算1/（1*4）+1/（4*7）+1/（7*10)+------+1/(97*100)································································································ 在等腰三角形ABC中,AB=AC.求证1、∠BAD=∠CAE 2、如果AD=AE,那么BD=CE吗?急啊························································· 证明1·3·5·····(2n-1)/2·4·6·····2n 这几道奥数题谁会,求2014在哪一行那一列 1 2 3 4 5 10 9 8 7 6 11 12 13 14 15 20 19 18 17 16 求2014哪一行那一列 1 2 3 4 5 6 7 8 9 ···· ····· ·························· 1+2++3+··········+10000= 8+11+14+17+20+·······+305 数学计算题.呜呜呜1+2+3+4+···················+98+99+100+99+98+···············+3+2+1 观察1/2 1/6 1/12 1/20 1/30·····的排列顺序,第60个数是多少?观察1/2 1/6 1/12 1/20 1/30··························的排列顺序,第60个数是多少? 将下列每个3*3正方形内的九格以及横竖九格均填入一至九的数字,且不重复.· 8 9 · 2 ··1··· 1 ··· 3······· 6 7········· 8 2·········5 ···· 7 ··············· 9 8 ····7 · 1/2+1/6+1/12+·····+1/90怎么算 水通电分解在1-6min内,生成氢气与氧气的比值大于2：1,可能的原因是：····························从第7min开始,生成氢气与氧气的比值等于2：1可能的原因是 ············· 观察下列三角形数表其中从第二行起每行的每一个数为其肩膀上两树之和则该表的最后一个数是?1 2 3 4 5 6 7 8················ 97 98 99 100 3 5 7·························· 1-1/2+1/6+1/12+1/20+·········+1/72+1/90巧算