nynw.net
当前位置:首页 >> 已知A=2015x+2016,B=2015x+2017,C=2015x+2015,则多... >>

已知A=2015x+2016,B=2015x+2017,C=2015x+2015,则多...

a²+b²+c²-ab-ac-bc=1/2[(a-b)^2+(b-c)^2+(c-a)^2]=1/2[1+4+1]=3

解: a²+b²+c²-ab-bc-ca =(1/2)*(2a²+2b²+2c²-2ab-2bc-2ca) =(1/2)*(a²-2ab+b²+c²-2ca+a²+b²-2bc+c²) =(1/2)*[(a-b)²+(a-c)²+(b-c)²] 易知: a-b=-1 b-c=-1 a-c=-2...

a^2+b^2+c^2-ab-bc-ac =2x1/2(a^2+b^2+c^2-ab-bc-ac) =1/2(2a^2+2b^2+2c^2-2ab-2bc-2ac) =1/2(a^2-2ab+b^2+b^2-2bc+c^2+a^2-2ac+c^2) =1/2[(a-b)^2+(b-c)^2+(a-c)^2] 把a,b,c的值代入上式得=1/2[(-1)^2+(-1)^2+(-2)^2]=1/2(1+1+4)=3

∵a,b是方程x2-x-2014=0的两个实数根,∴a2-a-2014=0,∴a2-a=2014,又∵a+b=1,∴a2+2a+3b=(a2-a)+3(a+b)=2014+3×1=2017.故选:C.

2015×2016-2014×2017 =2015x(2017-1)-2014x2017 =2015x2017-2015-2014x2017 =(2015-2014)x2017-2015 =1x2017-2015 =2

2016^3 -2016 =2016.(2016^2-1) =2016.(2016-1)(2016+1) =2016x2015x2017 ans : D(2014)

解: x=-2016 |x²+2015x+1|+|x²+2017x-1| =|x²+2015x-2016+2017|+|x²+2017x+2016-2017| =|(x-1)(x+2016)+2017|+|(x+1)(x+2016)-2017| =|0+2017|+|0-2017| =2017+2017 =4034 选C 提示:既然x=-2016,也就是x+2016=0,那么就...

a>b>c, ln(x+3)/x在(x

因为 [(2017-x)-(2015-x)]^2=(2017-x)^2+(2015-x)^2-2(2017-x)(2015-x) 则(2017-x)^2+(2015-x)^2= [(2017-x)-(2015-x)]^2+2(2017-x)(2015-x)=2^2+2*2016=4036 (2017-x)的平方+(2015-x)的平方的值为4036.

2017 =2016-1-2015/2017x(2017-2) =2016/解:原式=2016/2017x2 =2016-4032/2017x2015 =2016/2017 =2014又2/2017x2017-2016/2017 分析

网站首页 | 网站地图
All rights reserved Powered by www.nynw.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com