(1-1/2)*(1-1/3)*·······*(1-1/2013)等于多少?

急·····················1+2+3+...+999=? 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 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 秦始皇和汉武帝各自的功劳是?（用1·······2·······3··········来说） 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····· 证明1·3·5·····(2n-1)/2·4·6·····2n 已知三个角1,2,3满足：1与2互补,2与3互余,试求1-3的大小!································· 1/3+2/3=1,但0.333···+0.666···=0.999···,为神马?额······谁能解释一下······ 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 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, 2[4/3y—（2/3y—1/2）]=3/4y急·································!1 数列 1/2,3/2,1/3 ,4/3,·········1/n+1,n+2/n+1,·········是否有极限? 计算1/（1*4）+1/（4*7）+1/（7*10)+------+1/(97*100)································································································ 贡献和呼吁的造句?急急急急急都写三个，1、贡献····· 2、··· 3、······ 1、呼吁····· 2、······ 3、······· 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 · 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························································· 1+1/（1+2）+1/（1+2+3）+·····+1/(1+2+3+·····+n) 求和