求（1-x）^3展开式的各项系数
\u5728(1+x)^3\u00b7(1+1/x)^3\u7684\u5c55\u5f00\u5f0f\u4e2d,\u542b1/x\u7684\u9879\u7684\u7cfb\u6570\u4e3a\u8ba1\u7b97\u540e\uff1a15
(1+x)^6\u4e2dx^3\u6b21\u9879(\u5305\u62ecx^3\u6b21\u9879)\u4ee5\u4e0b\u7684\u9879\u67091\uff0c6x,15x^2,20x^3
(1-x)^4\u4e2dx^3\u6b21\u9879(\u5305\u62ecx^3\u6b21\u9879)\u4ee5\u4e0b\u7684\u9879\u67091\uff0c-4x,6x^2,-4x^3
\u90a3\u4e48x^3\u7cfb\u6570\u4e3a
20-4-60+36=-8
＝（1＋x平方－2x）＊（1-x）
＝1-x三次方＋x平方－x三次方－2x＋2x平方
＝1-2x三次方＋3x平方－2x
网上有例题呀
2^3=8
等于 1-3x+x^3 满意就采纳
绛旓細锛1- x锛锛锛1锛峹锛锛锛1-x锛锛濓紙1锛媥骞虫柟锛2x锛夛紛锛1-x锛夛紳1-x涓娆℃柟锛媥骞虫柟锛峹涓夋鏂癸紞2x锛2x骞虫柟 锛1-2x涓夋鏂癸紜3x骞虫柟锛2x
绛旓細(1-x)(1-x)(1-x)=(1-x)(1-2x+x2)=1-2x+x2-x+2x2-x3=1-3x+3x2-x3 杩介棶 缁欓敊璇勪环浜,浣犵殑绛旀鏄敊鐨 鍥炵瓟 閭ｆ垜鐪嬬湅浠婂ぉ璋佸 璇勮| 2013-09-29 15:27瀵掓ū鏆栨殩|鍗佷笁绾 1-X^3=(1-X)(1+X+X^2) =1-3x+3x²-x³甯屾湜鑳藉府鍒颁綘,璇烽噰绾! 杩介棶 璋㈣阿浣犵殑绛旀 鍥炵瓟 涓嶅姘,璇烽噰...
绛旓細(1-x)^3 =1-3x+3x^2-x^3
绛旓細姹(1-x)³(x²-2x+3)³鐨灞曞紑寮涓鍚勯」绯绘暟鐨勭粷瀵瑰间箣鍜 瑙ｏ細(1-x)³(x²-2x+3)³=[(1-x)(x²-2x+3)]³=(-x³+3x²-5x+3)³浠=1锛屽苟鍙栧悇椤圭粷瀵瑰间箣鍜屽緱(1+3+5+3)³=12³=1728 ...
绛旓細绗竴涓x²绯绘暟涓 3 绗簩涓獂²绯绘暟涓 6 鈥︹︹︾n涓獂²绯绘暟涓 n(n-1)/2 鎵浠 x² 绯绘暟涓 3+6+鈥︹︹+n(n-1)/2 =(1/2)[3²+4²+鈥︹︹+n²-(3+4+5+鈥︹︹+n)]=(1/2)[n(n+1)(2n+1)/6-5-n(n+1)/2+3]=(1/2)...
绛旓細锛1-x)^3(1+x)^5 =(1-x^2)^3 . (1+x)^2 =(1-3x^2+3x^4 -x^6) .(1+x)^2 coef.of x^4 =-3x1 + 3x1 =-3 +3 =0
绛旓細鎵姹傚嵆涓哄悇浜岄」寮弜^2椤圭殑绯绘暟涔嬪拰锛屼互涓嬬敤rCn琛ㄧずn鍙杛鐨勬帓鍒 鎵姹=2C3+2C4+2C5+鈥︹+2Cn =-1+3C4+2C4+2C5+鈥︹+2Cn =-1+3C5+2C5+鈥︹+2Cn =鈥︹=-1+3C锛坣+1)=(n^3-n-6)/6
绛旓細浠や簩椤瑰紡涓墍鏈夌殑瀛楁瘝閮界瓑浜1锛屽垯璁＄畻鍑虹殑缁撴灉灏辩瓑浜庝簩椤瑰紡灞曞紑寮忕殑鍚勯」绯绘暟鐨勫拰銆傚锛氾紙5x-1/鏍瑰彿x锛鐨刵娆℃柟鐨勫睍寮寮忓悇绯绘暟涔嬪拰涓篗锛屽叾涓璏鐨勭畻娉曚负锛氫护x=1锛屽緱4^n锛涗簩椤瑰紡绯绘暟涔嬪拰涓篘锛屽叾涓璑鐨勭畻娉曚负锛2^n锛屼粠鑰屾湁4^n-2^n=56銆傝В杩欎釜鏂圭▼锛56=7*8锛岃4^n-2^n=锛2^n锛*锛2^n-...
绛旓細绠鍗曡锛屽氨鏄睍寮鍚鍚勯」鐨勭郴鏁板惂銆傛垜閲嶆柊瑙ｇ瓟涓涓嬪惂銆傚綋n涓哄伓鏁版椂锛锛1-x)^n=锛坸-1)^n 灞曞紑寮涓浜岄」锛岀涓夐」锛岀鍥涢」鐨勪簩椤瑰紡绯绘暟鍒嗗埆涓 Cn 1 C n 2 Cn 3 鐢遍鐭 2C n 2 = C n 1 + C n 3 鍗 2* n(n-1)/(2*1)=n+ n(n-1)(n-2)/(3*2*1)瑙ｅ緱n=0(...
绛旓細浠x=1锛屽緱鍒鍚勯」绯绘暟鍜 浠=-1锛屽緱鍒板鏁版椤逛负璐燂紝鍋舵暟娆￠」涓烘 0^11-2^11涓轰袱鍊嶅鏁版椤圭郴鏁板拰 鏁呭鏁版椤圭殑绯绘暟鍜屼负-2^10
