新人教版八年级上期末数学检测卷B二

1、2013-2014学年新人教版八年级（上）期末数学检测卷b（二）一、选择题（每小题3分，共24分）1下列图案中不是轴对称图形的是（）abcd 显示解析2下列运算结果正确的是（）aa3a4=a12b（a2）3=a6c（3a）3=3a3da（a+1）=a2+1 显示解析3下列说法中：三条线段组成的图形叫做三角形；三角形的角平分线是射线；三角形的三条高所在的直线相交于一点，这一点不在三角形的内部，就在三角形的外部；三角形的三条中线相交于一点，且这点一定在三角形的内部其中正确的有（）a4个b3个c2个d1个 显示解析4下列说法不正确的是（）a在锐角三角形中，最大的锐角x的

2、取值范围是60°x90°b在abc中，锐角的个数最多c在abc中三个内角：=1：3：5，这个三角形是直角三角形d一个三角形中至少有一个角是锐角 显示解析5下列条件中，能判定abcdef的是（）aab=de，bc=ef，a=dba=d，c=f，ac=efcb=e，a=d，ac=efdb=e，a=d，ab=de 显示解析6下列分解因式正确的是（）am3-m=m（m-1）（m+1）bx2-x-6=x（x-1）-6c2a2+ab+a=a（2a+b）dx2-y2=（x-y）2 显示解析7对于分式2x+a3x1，当x=-a2时，下列说法中：分式值一定为0；

3、分式一定有意义；当a=-23时，分式无意义其中正确的个数有（）a3个b2个c1个d0个 显示解析8如图，在rtabc中，ab=cb，boac，把abc折叠，使ab落在ac上，点b与ac上的点e重合，展开后，折痕ad交bo于点f，连接de、ef下列结论：tanadb=2；图中有4对全等三角形；若将def沿ef折叠，则点d不一定落在ac上；bd=bf；s四边形dfoe=saof，上述结论中正确的个数是（）a1个b2个c3个d4个 显示解析二、填空题（每小题3分，共24分）9已知等腰三角形的一个内角为40°，则这个等腰三角形的顶角为  显示解析10化

4、简：（a2b）-2（a-1b-2）-3=  显示解析11如图，abc中，ab=ac，a=30°，de垂直平分ac，则bcd的度数为  显示解析12如图，在abc中，ab=ac，b=30°，ab的垂直平分线ef交ab于点e，交bc于点f，ef=2，则bc的长为  显示解析13如果（a+b）2=19，a2+b2=14，则（a-b）2=  显示解析14如图，在abc中，ab=a，ac=b，bac=150°，则sabc=  显示解析15如图，在abc中，ad为bc边上的中线

5、已知ac=5，ad=4，则ab的取值范围是  显示解析16关于x的分式方程mx1+31x1的解为正数，则m的取值范围是  显示解析三、解答题（其中17，18题各9分，19，21，22，24，26题各10分，20题12分，23题8分，25题14分，共102分）17已知2x+y=4，求代数式（x+y）2-（x-y）2-2y（x-12y）÷4y的值 显示解析18（1）计算：a1a÷（a-2a1a）（2）解方程：23+x3x1=19x3 显示解析19有公路l1同侧、l2异侧的两个城镇a，b，如下图电信部门要修建一座信号发射

6、塔，按照设计要求，发射塔到两个城镇a，b的距离必须相等，到两条公路l1，l2的距离也必须相等，发射塔c应修建在什么位置？请用尺规作图找出所有符合条件的点，注明点c的位置（保留作图痕迹，不要求写出画法） 显示解析20如图，在abc中，ab=ac，点d、e、f分别在边ab、bc、ac上，且bd=ce，def=b图中是否存在和bde全等的三角形？说明理由 显示解析21甲、乙两人准备整理一批新到的实验器材若甲单独整理需要40分钟完工：若甲、乙 共同整理20分钟后，乙需再单独整理20分钟才能完工（1）问乙单独整理多少分钟完工？（2）若乙因工作需要，他的整理时间不超过30分钟

7、，则甲至少整理多少分钟才能完工？ 显示解析22如图，已知点d为等腰直角abc内一点，cad=cbd=15°，e为ad延长线上的一点，且ce=ca（1）求证：de平分bdc；（2）若点m在de上，且dc=dm，求证：me=bd 显示解析23某种产品的原料降价，因而厂家决定对产品进行降价现有两种方案：方案1：第一次降价p%，第二次降价q%方案2：第一、二次降价均为p+q2%其中p，q是不相等且使此情境有意义的正数，两种方案哪种降价最多？ 显示解析24一块原边长分别为a，b（a1，b1）的长方形，一边增加1，另一边减少1（1）当a=b时，变化后的面积是增加还是

8、减少？（2）当ab时，有两种方案，第一种方案如图1，第二种方案如图2请你比较这两种方案，确定哪一种方案变化后的面积比较大 显示解析25如图1，在正方形abcd中，点m、n分别在ad、cd上，若mbn=45°，易证mn=am+cn（1）如图2，在梯形abcd中，bcad，ab=bc=cd，点m、n分别在ad、cd上，若mbn=12abc，试探究线段mn、am、cn有怎样的数量关系？请写出猜想，并给予证明（2）如图3，在四边形abcd中，ab=bc，abc+adc=180°，点m、n分别在da、cd的延长线上，若mbn=12abc，试探究线段mn、am、cn又有怎样的

9、数量关系？请直接写出猜想，不需证明 显示解析26在abc中，a=90°，点d在线段bc上，edb=12c，bede，垂足为点e，de与ab相交于点f当ab=ac时（如图所示）（1）ebf= （2）探究线段be与fd的数量关系，并加以证明v7xav2ohum32wgeauwydiawgmer4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgz7r4i30ka1dkagtgkqcwa3p tgz7r4i30ka1dkaghn3xtkknbycudxqa7fhyi2chhi92tgkqcwa3ptgshls50clmtw

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