1/1*2+1/2+3+···1/2002*2003+1/2003*2004+1/2004*2005

急·····················1+2+3+...+999=? 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 1+2++3+··········+10000= 1/（1+2）+1/（1+2+3）+1/（1+2+3+4）+······+1/（1+2+3+······+200）=? 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 根据1+2+3+4+······+n=n(n+1）/2 计算2+4+6+····+200 证明1·3·5·····(2n-1)/2·4·6·····2n 秦始皇和汉武帝各自的功劳是?（用1·······2·······3··········来说） 数列 1/2,3/2,1/3 ,4/3,·········1/n+1,n+2/n+1,·········是否有极限? 1+1/（1+2）+1/（1+2+3）+·····+1/(1+2+3+·····+n) 求和 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······ 2[4/3y—（2/3y—1/2）]=3/4y急·································!1 (1+1/2+1/3+···+1/2003)(1/2+1/3+···+1/2004)-(1+1/2+1/3+···+1/2004)(1/2+1/3+···+1/2003) (1/2+1/3···+1/2003)(1+1/2+1/3+···+1/2004)-(1+1/2+1/3+···+1/2003)(1/2+1/3+···+1/2004) 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····· 某大学有两栋宿舍楼,1号楼里住着200名学生,2号楼里住着300名学生.两楼相距900米.如图1号楼·············································900米·················· (1-1/2)*(1-1/3)*·······*(1-1/2013)等于多少?