若a=2005,b=2006,c=2007,求a2+b2+c2-ab-bc-ac的值.
人气:201 ℃ 时间:2019-10-17 01:52:42
解答
∵a=2005,b=2006,c=2007,
∴a-b=-1,a-c=-2,b-c=-1,
则原式=
×2(a
2+b
2+c
2-ab-bc-ac)
=
[(a-b)
2+(a-c)
2+(b-c)
2]
=3.
推荐
猜你喜欢
- 甲乙两车从相距190KM的AB两地相向开出,在途中相遇,已知甲,乙两车的速度比是4:3,相遇时所开出的时间比是5:6,求甲乙两车相遇时各行了多少千米?
- 1*9+2 9*9+7
- 有一根木棒,一头粗 ,一头细.在其重心处支撑起来,木棒可在水平面内平衡,现在从重心处将它截成俩段,则( )
- Susan wants (six bottles)of milk括号部分提问
- Much of this sucess is because of the work of Chinese scientists,with support from other
- 在直角三角形ABC中,D是斜边AB的中点,AC=6cm,BC=8cm,EC垂直平面ABC,EC=12cm,求EA,EB,ED.
- The watch is very nice.He gave me the watch for my birthday.合并成定语从句的复合句
- sinx整体的平方是谁的导数啊