新人教版八年级（上）期末数学检测卷B（一）

1、2013-2014学年新人教版八年级（上）期末数学检测卷b（一）一、选择题（每小题3分，共24分）1下列图形中，不是轴对称图形的是（）abcd显示解析2下列各式中计算正确的是（）ax+x3=x4b（x-4）2=x8cx-2x5=x3dx8x2=x4（x0）显示解析3下列各式中与分式nmn相等的是（）anmnbnm+ncnnmd-nnm显示解析4一个四边形，截一刀后得到新多边形的内角和将（）a增加180b减少180c不变d以上三种情况都有可能显示解析5如图，abc中，ad、be是两条中线，则sedc：sabc=（）a1：2b2：3c1：3d1：4显示解析6等腰三角形腰上的高与底边的夹角等于（）a

2、底角b底角的一半c顶角d顶角的一半显示解析7下列各式是最简分式的是（）ax24y2(x+2y)2bx2+y2x+yc2xy9x3dx2+xx21显示解析8若关于x的方程2x+k=3x+3有正数根，则k的取值范围是（）ak2bk3c-3k-2dk2且k-3显示解析二、填空题（每小题3分，共24分）9观察图形规律：（1）图中一共有个三角形，图中共有个三角形，图中共有个三角形（2）由以上规律进行猜想，第n个图形共有个三角形显示解析10计算：（-12）-2（-2）2=显示解析11若（2x+3）0=1，则x满足条件显示解析12a2+b2=5，ab=2，则a-b=显示解析13如图，在abc中，ab=ac，

3、d，e分别是ac，ab上的点，且bc=bd，ad=de=eb，则a=度显示解析14若分式x29x2x6=0，则x=显示解析15在公式e=irn+ir中，所有字母都不等于零，则用e、n、r、r表示i为显示解析16如图，在平面直角坐标系xoy中，a（2，1）、b（4，1）、c（1，3）与abc与abd全等，则点d坐标为显示解析三、解答题（其中17、18题各9分，19，21，22，24，26题各l0分，20-n12分，23题8分，25题14分，共102分）17先化简，再求值：（4ab3-8a2b2）4ab+（2a+b）（2a-b），其中a=2，b=1显示解析18（1）计算：1-aba+2ba2b2a

4、2+4ab+4b2（2）解方程：4x21+x+21x=-1显示解析19如图，在平面直角坐标系中，点a的坐标是（4，0），点b的坐标是（2，3），点c的坐标是（0，3）（1）作出四边形oabc关于y轴对称的图形，并标出点b对应点的坐标（2）在y轴上找一点p，使pa+pb的值最小，并求出点p的坐标（要求不写作法，保留作图痕迹）显示解析20如图，将rtabc的直角顶点c置于直线l上，ac=bc，过a、b两点分别作直线l的垂线，垂足分别是点d、e若be=3，de=5，求ad的长显示解析21甲、乙两位采购员同去一家饲料公司购买两次饲料两次饲料的价格有变化，两位采购员的购货方式也不同，其中，甲每次购买10

5、00千克，乙每次用去800元，而不管购买多少饲料（1）甲、乙所购饲料的平均单价各是多少？（2）谁的购货方式更合算？显示解析22如图，在abc中，ab=ac，bac=45，ad和ce是abc的高，且ad和ce相交于点h，求证：ah=2bd显示解析23甲、乙两工程队分别承担一条2千米公路的维修工作，甲队有一半时间每天维修公路x千米，另一半时间每天维修公路y千米乙队维修前1千米公路每天维修x千米；维修后1千米公路时，每天维修y千米（xy）（1）求甲、乙两队完成任务需要的时间（用含x、y的代数式表示）；（2）问甲、乙两队哪队先完成任务？显示解析24已知将边长分别为a和2b（ab）的长方形分割成四个全等

6、的直角三角形，如图1，再用这四个三角形拼成如图2所示的正方形，中间形成一个正方形的空洞经测量得长方形的面积为24，正方形的边长为5试通过你获取的信息，求a2+b2和a2-b2的值显示解析25数学课上，李老师出示了如下的题目：“在等边三角形abc中，点e在ab上，点d在cb的延长线上，且ed=ec，如图，试确定线段ae与db的大小关系，并说明理由”小敏与同桌小聪讨论后，进行了如下解答：（1）特殊情况，探索结论当点e为ab的中点时，如图1，确定线段ae与db的大小关系，请你直接写出结论：aedb（填“”，“”或“=”）（2）特例启发，解答题目解：题目中，ae与db的大小关系是：aedb（填“”，“

7、”或“=”）理由如下：如图2，过点e作efbc，交ac于点f（请你完成以下解答过程）（3）拓展结论，设计新题在等边三角形abc中，点e在直线ab上，点d在直线bc上，且ed=ec若abc的边长为1，ae=2，求cd的长（请你直接写出结果）显示解析26如图1，在abc中，ab=ac，d是ac延长线上一点，点e在射线db上，且有bac=ced=，连接ea求证：ea平分bec（说明：如果反复探索没有解题思路，可以从下列条件中选取一个加以解决：如图2，=60；如图3，=90）92tgkqcwa3ptgshls50clmtwn60eo8wgqv7xav2ohum32wgeauwydiawgmer4i30

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