问题标题:
①已知x^2y^2-4xy+x^2-2x+5=0求1/xy+1/(x+1)(y+1)+1/(x+2)(y+2)+…+1/(x+2009)(y+2009)的值②计算[(1994^2-2000)(1994+3985)×1995]/(1991×1993×1996×1997)③设x=-2-√3,求x5+6x4+7x3-4x2-8x+1的值④若√(2x-3)+y=4,化简√(x^2-2x+1)+
问题描述:
①已知x^2y^2-4xy+x^2-2x+5=0求1/xy+1/(x+1)(y+1)+1/(x+2)(y+2)+…+1/(x+2009)(y+2009)的值
②计算[(1994^2-2000)(1994+3985)×1995]/(1991×1993×1996×1997)
③设x=-2-√3,求x5+6x4+7x3-4x2-8x+1的值
④若√(2x-3)+y=4,化简√(x^2-2x+1)+√(y^2-8y+16)
⑤x=√(3+√2),y=√(3-√2),求x^6+y^6的值
⑥若a>1,p=√2001a-√(2001a-1),q=√(2001a-1)-√2001a,r=√2001a-√(2001a+1),s=√(2001a+1)-√2001a,试比较p,q,r,s的大小,并求出最小的一个
苏国锋回答:
1、x^2y^2-4xy+x^2-2x+5=0(x^2y^2-4xy+4)+(x^2-2x+1)=0(xy-2)^2+(x-1)^2=0两个平方只有都等于0所以xy-2=0,x-1=0x=1,y=2所以原式=1/1*2+1/2*3+……+1/2010*2011=1-1/2+1/2-1/3+……+1/2010-1/2011=1-1/2011=2010/2011...
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