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①已知a=2008x+2004,b=2008x+2005,c=2008x+2006,求a的二次方+b的二次方+c的二次方
题目内容:
①已知a=2008x+2004,b=2008x+2005,c=2008x+2006,求a的二次方+b的二次方+c的二次方-ab—ac—bc的值
②已知x+y+z=2,xy+yz+xz=-5,求x的二次方+y的二次方+z的二次方的值
③(2+1)(2的二次方+1)(2的四次方+1)……(2的六十四次方+1)+1
④若x的三次方—5 x的二次方+10x—6=(x—1)(x的二次方+ax+b)成立,试求a、b的值
⑤若(x的二次方+nx+3)(x的二次方—3x+m)的展开式中不含x的二次方和x的三次方项,求(—m)的n次方的值
⑥若二项式4m的二次方+1加上一个单项式后是一含m的完全平方式,则单项式为?
注:⑤题要写过程,最后一题只要写答案优质解答
①a^2 + b^2 + c^2 - ab - ac - bc = 1/2 * (2a^2 + 2b^2 + 2c^2 - 2ab - 2ac - 2bc)
= 1/2 [ (a-b)^2 + (b-c)^2 + (a-c)^2 ] = 1/2 * (1+1+4) = 3
② (x+y+z)^2 = x^2 + y^2 + z^2 + 2xy + 2xz + 2yz
则x^2 + y^2 + z^2 = (x+y+z)^2 - 2(xy+yz+xz)= 2^2 - 2*(-5) = 14
③(2+1)(2^2+1)(2^4+1)… (2^64+1)+ 1
= (2-1)(2+1)(2^2+1)(2^4+1)… (2^64+1)+ 1
= (2^2-1)(2^2+1)(2^4+1)… (2^64+1)+ 1
=(2^4-1)(2^4+1)… (2^64+1)+ 1
= ……
= 2^128 - 1 + 1 = 2^128
④ 因为 x^3 - 5x^2 + 10x - 6 = (x - 1) (x^2 + ax +b) = x^3 - (1 - a)x^2 + (b - a)x - b
所以 1 - a = 5 ,b - a = 10 ,b = 6
所以 a= -4 b = 6
⑤ ( x^2 + nx + 3) ( x^2 - 3x + m) = x^4 + (n-3)x^3 + (m-3n+3)x^2 + (mn-9)x + 3m
依题得 n-3 = 0 m-3n+3 = 0
解得 m = 6 ,n = 3
⑥ 单项式为 am + (a^2)/16 - 1 ( a 不等于 0 )
②已知x+y+z=2,xy+yz+xz=-5,求x的二次方+y的二次方+z的二次方的值
③(2+1)(2的二次方+1)(2的四次方+1)……(2的六十四次方+1)+1
④若x的三次方—5 x的二次方+10x—6=(x—1)(x的二次方+ax+b)成立,试求a、b的值
⑤若(x的二次方+nx+3)(x的二次方—3x+m)的展开式中不含x的二次方和x的三次方项,求(—m)的n次方的值
⑥若二项式4m的二次方+1加上一个单项式后是一含m的完全平方式,则单项式为?
注:⑤题要写过程,最后一题只要写答案
优质解答
= 1/2 [ (a-b)^2 + (b-c)^2 + (a-c)^2 ] = 1/2 * (1+1+4) = 3
② (x+y+z)^2 = x^2 + y^2 + z^2 + 2xy + 2xz + 2yz
则x^2 + y^2 + z^2 = (x+y+z)^2 - 2(xy+yz+xz)= 2^2 - 2*(-5) = 14
③(2+1)(2^2+1)(2^4+1)… (2^64+1)+ 1
= (2-1)(2+1)(2^2+1)(2^4+1)… (2^64+1)+ 1
= (2^2-1)(2^2+1)(2^4+1)… (2^64+1)+ 1
=(2^4-1)(2^4+1)… (2^64+1)+ 1
= ……
= 2^128 - 1 + 1 = 2^128
④ 因为 x^3 - 5x^2 + 10x - 6 = (x - 1) (x^2 + ax +b) = x^3 - (1 - a)x^2 + (b - a)x - b
所以 1 - a = 5 ,b - a = 10 ,b = 6
所以 a= -4 b = 6
⑤ ( x^2 + nx + 3) ( x^2 - 3x + m) = x^4 + (n-3)x^3 + (m-3n+3)x^2 + (mn-9)x + 3m
依题得 n-3 = 0 m-3n+3 = 0
解得 m = 6 ,n = 3
⑥ 单项式为 am + (a^2)/16 - 1 ( a 不等于 0 )
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