1+2+3+4一直到N用N怎么表示？
-1\uff0c2,-3,+4\u2026\u2026\u2026\u7b2cn\u4e2a\u600e\u4e48\u8868\u793a\uff1f1+1/1+2+1/1+2+3+1/1+2+3+4+\u2026\u2026+1/1+2+3\u2026\u2026+n \u63a8\u5bfc\u8fc7\u7a0b\uff1a 1+1/(1+2)+1/(1+2+3)+1/(1+2+3+4)+\u2026\u2026+1/(1+2+3\u2026\u2026+n) = 1+1/[(1+2)\u00d72\u00f72]+1/[(1+3)\u00d73\u00f72]+\u2026\u2026+1/[(1+n)\u00d7n\u00f72]\u2014\u2014\u2460 = 2/2+2/(1+2)\u00d72+2/(1+3)\u00d73+\u2026\u2026+2/(1+n)\u00d7n\u2014\u2014\u2461 = 2\u00d7[1/2+1/2-1/3+1/3-1/4+\u2026\u2026+1/n-1/(1+n)]\u2014\u2014\u2462 = 2\u00d7[1-1/(1+n)] = 2\u00d7[n/(1+n)] = 2n/(1+n) \u6ce8\u91ca\uff1a \u2460\u628a\u5206\u6bcd\u7b49\u5dee\u6570\u5217\u5199\u6210\u7b80\u4fbf\u5f62\u5f0f \u2461\u5206\u5b50\u548c\u5206\u6bcd\u540c\u65f6\u4e58\u4ee52 \u2462\u628a\u5206\u5b502\u63d0\u51fa\u6765\u505a\u516c\u56e0\u6570
1+2+3+4+……+N=（1+N）*N/2回答完毕~望采纳~O(∩_∩)O谢谢你好：你可以这样表示：S=1+2+3+...+N也可以这样表示：N∑j=1
NX（1+N）/2
绛旓細=N(1+N)/2 鏈涢噰绾筹紝O(鈭鈭)O璋㈣阿
绛旓細鑷劧鏁n鐨勯樁涔樺啓浣渘!銆1808骞达紝鍩烘柉椤柯峰崱鏇煎紩杩涜繖涓〃绀烘硶銆傞樁涔樻寚浠1涔樹互2涔樹互3涔樹互4涓鐩涔樺埌鎵瑕佹眰鐨勬暟銆備緥濡傛墍瑕佹眰鐨勬暟鏄4锛屽垯闃朵箻寮忔槸1脳2脳3脳4锛屽緱鍒扮殑绉槸24锛24灏辨槸4鐨勯樁涔樸 渚嬪鎵瑕佹眰鐨勬暟鏄6锛屽垯闃朵箻寮忔槸1脳2脳3脳鈥︹γ6锛屽緱鍒扮殑绉槸720锛720灏辨槸6鐨勯樁涔樸
绛旓細鎵浠ワ紝1鍔鍒皀鐨勫拰鐨勫叕寮忎负锛歋_n=n/2脳锛1+n锛夈傝В閲婏細杩欎釜鍏紡鏄氳繃绛夊樊鏁板垪姹傚拰鍏紡璁＄畻鍑烘潵鐨勩傚畠灏唍涓暟瀛楃浉鍔狅紝寰楀埌瀹冧滑鐨勬诲拰銆傚綋n涓1鏃讹紝鎬诲拰涓1锛涘綋n涓2鏃讹紝鎬诲拰涓3锛涘綋n涓3鏃讹紝鎬诲拰涓6锛涗互姝ょ被鎺ㄣ傚叕寮忕殑浣滅敤锛1銆佸簲鐢ㄤ簬璁＄畻鍜屾眰瑙ｉ棶棰樸傞氳繃浣跨敤鍏紡锛屾垜浠彲浠ュ皢澶嶆潅鐨勯棶娑叉媶鍦...
绛旓細鍥炵瓟锛1鍔n 涔樹互n 闄や互2
绛旓細1^3+2^3+3^3+鈥︹+n^3=[n(n+1)/2]^2.1^4+2^4+3^4+鈥︹+n^4=(1/5)n^5+(1/2)n^4+(1/3)n^3-(1/30)n.
绛旓細涓句釜渚嬪瓙 鍋囧n=3 鍒欙紙1*2*3*4鈥︹*n锛!= 锛1*2*3锛夛紒=3锛侊紒=6锛=6脳5脳4脳3脳2脳1 鎹㈡垚n閬撶悊涓鏍 绁濅綘寮蹇
绛旓細int n = 10;//鏀规垚浣犺嚜宸遍渶瑕佺殑nint sum = 0;for(int i = 1; i <= n; ++i){ sum += i;}double average = sum * 1.0 / n;//骞冲潎鍊
绛旓細1+2+3+4+5+6+...N =锛n+1锛塶梅2 =n锛坣+1锛/2
绛旓細浠1+2+3+鈥+99+100涓轰緥锛岀涓浣嶅拰鏈鍚庝竴浣嶇浉鍔犳槸 1+100=101 绗浜浣嶅拰鍊掓暟绗簩浣嶇浉鍔犳槸 2+99=101 浠ユ绫绘帹锛屼竴鍏变竴鐧句釜鏁板叡鏈50涓101锛岀浉褰撲簬涓鐧句釜鏁伴櫎浠2锛屾墍浠ュ叕寮忔槸 (1+n)脳n梅2 鍒拌繖閲屾槸涓嶆槸闄や互2鏄庝箞鍥炰簨浜嗐
绛旓細濡傛灉鎴戜滑鍙互鐢╪鈥昏〃绀簄*(n-1)*(n-2)...*2*1,閭ｄ箞n锛冿紳n鈥
