(完整)二次根式提高培优题

(完整)二次根式提高培优题

1.已知a为实数，则代数式xy的值为（）A．2B．（a+b）C．9D．（a-b）2.若x=-2，y=3，则二次根式的最小值为（）A．0B．3C．-1D．23.直线l：y=(m-3)x+n-2（m，n为常数）的图象如图，化简：|m-3|-|n-1|的值为（）A．3-m-nB．5C．-1D．m+n-54.若整数m满足条件|m+1|=m+1且m＜1，则m的值是（）A．-1或1B．-1、或1C．或-1D．-15.观察下列计算：（++）（+…+）的结果为（）A．2008B．2010C．2011D．20096.已知实数a在数轴上的位置如图所示，则化简|1-a|+|2a-1|的值为（）A．1B．-1C．1-2aD．2a-17.若式子（a-1）2+(b-2)2=4有意义，则点P（a，b）在（）A．第一象限B．第二象限C．第三象限D．第四象限8.对于以下四个命题：①若直角三角形的两条边长为3与4，则第三边的长是5；②若点P（a，b）在第三象限，则点Q（-a，-b）在第一象限；③两边及其第三边上的中线对应相等的两个三角形全等；④正确的说法是（）A．只有①错误，其他正确B．①②错误，③④正确C．①④错误，②③正确D．只有④错误，其他正确9.如果a>0，b>0，且a/b>1，那么（）A．a=bB．a＞bC．a＜bD．a•b=110.已知：a+b=6，ab=15，则代数式（3a2-18a+15）（2b2-12b+13）的值是（）A．-3B．3C．2x-5D．5-2x11.已知：1＜x＜3，则x2-4x+3的值域为（）A．2B．3C．4D．512．已知整数X，Y满足X2-Y2=2019，那么整数对（X，Y）的个数是（）A．2B．3C．4D．513．计算：（1+2+3+…+2019）-（1+3+5+…+2019）的值为（）A．1009B．1010C．2019D．202014．对于X，Y定义一种新运算“*”：X*Y=aX+bY，其中a，b为常数，等式右边是通常的加法和乘法的运算．若2*（3*4）=10，且3*（4*5）=19，则5*（6*7）的值为（）A．33B．34C．35D．3615．观察下列二次根式的化简：√(4x2+4x+1)-√(4x2-4x+1)的结果为（）A．2x-1B．2x+1C．4x-1D．4x+116．若规定符号“*”的意义是a*b=ab-b2，则2*(3*4)的值为（）A．-18B．-12C．12D．1817．若[x]表示不超过x的最大整数（如[3.8]=3），则[(-1.5)-(-3.2)]的值为（）A．1B．2C．3D．4到规律，利用规律计算下列式子的值：1.规律：字符串相加可以将两个字符串拼接起来。利用这个规律，可以得到：[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[]+[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