2015-2016北京101中学双榆数校区初二上期中数学（含答案解析）

北京101中学双榆树校区2015-2016学年度第一学期中考 试卷 云南省高中会考试卷哪里下载南京英语小升初试卷下载电路下试卷下载上海试卷下载口算试卷下载 初二数学1、选择题：本大题共10小题，每题3分，共30分1．下列四个交通标志中，轴对称图形是（）．ABCD【答案】B【解析】根据轴对称图形的概念，轴对称图形两部分沿对称轴折叠后可重合，只有是轴对称图形．2．如图，正方形地砖的图案是轴对称图形，该图形的对称轴有（）．A．条B．条C．条D．条【答案】C【解析】根据轴对称图形的概念，轴对称图形两部分沿对称轴折叠后可重合，因此，由于正方形地砖的图案中间是正八边形，它们都有条对称轴，且重合．故选.3．下列运算结果正确的是（）．A.B.C.D.【答案】C【解析】选项，,故选项错误；选项，,故选项错误；选项，,故选项正确；选项，,故选项错误.4．已知点与点关于轴对称，则点的坐标为（）．A.B.C.D.【答案】C【解析】∵根据关于轴对称的点，横坐标相同，纵坐标互为相反数，∴点关于轴对称的点为，故选．5．若，则的值为（）．A．B．C．D．【答案】C【解析】∵，∴，∴，，∴.故选．6．在中，和的度数如下，其中能判定是等腰三角形的是（）．A．,B．,C．,D．,【答案】B【解析】选项，当顶角为时,，当顶角为时,,故选项错误；选项，当顶角为时,,故选项正确；选项，当顶角为时,，当顶角为时,,故选项错误；选项，当顶角为时,，当顶角为时,,故选项错误．7．等腰三角形的一个角为，则它的底角是（）．A．B．C．D．或【答案】D【解析】当等腰三角形顶角为，那么底角为，当等腰三角形的一个底角为时，则它的另一个底角是.故选．8．下列式子能运用平方差 公式 小学单位换算公式大全免费下载公式下载行测公式大全下载excel公式下载逻辑回归公式下载 分解的是（）．A．B．C．D．【答案】C【解析】平方差公式为，只有选项可以运用平方差公式分解。9．在下列各式的计算中，正确的是（）．A．B．C．D．【答案】B【解析】选项，,故选项错误；选项，,故选项正确；选项，,故选项错误；选项，,故选项错误.10．如图，中，,分别是边，上的点，作于，于，若,.下列结论：①;②;③≌，其中正确的是（）．A．①②③B．①②C．②③D．①③【答案】B【解析】①∵，∴在和中∴≌EMBEDEquation.DSMT4,∴.故①正确。②∵由①结论≌，∴.∵,∴，∴，∴，∵，∴.故②正确。③∵在和中，只有，，，∴不满足三角形全等的条件，故③是错误的。2、填空题:本大题共8小题，每空3分，共30分.11．__________；__________.【答案】；【解析】；.12．式子的公因式是__________；式子的公因式是__________.【答案】；【解析】∵，∴式子的公因式是.∵，∴式子的公因式是.13．已知如图，在中，，，,__________．【答案】【解析】∵中，∴∵，∴，∴，∵，∴.14．一个等腰三角形的两边长分别为和，则这个等腰三角形的周长是__________．【答案】【解析】（）若为腰长，为底边长，由于，则三角形不存在。（）若为腰长，为底边长，符合三角形的两边之和大于第三边。∴这个三角形的周长为.15．如图，是中边的垂直平分线，若，，则的周长为__________．【答案】【解析】∵是中边的垂直平分线，∴.∴的周长.16．如图，是等边三角形，点是边上任意一点，于点，于点，若边上高为，则__________．【答案】【解析】∵边上高为，∴,设，则.∵是等边三角形，∴,∴，∵，∴.17.若，，则__________．【答案】【解析】.18.，，则__________．【答案】【解析】.三、解答题：共8大题，满分60分19．计算：（每小题3分）（）．【解析】原式．（）．【解析】原式．（）．【解析】原式．（）．【解析】原式．20.先化简，再求值：，其中。（6分）【解析】原式.∵当时，∴.21．已知，求值.（6分）【解析】原式.∵.∴.∴原式.22．因式分解：(每小题3分)（）【解析】原式.（）【解析】原式.（）【解析】原式.（）【解析】原式.23．作图：第一小题4分，第二小题2分（）直线表示一条河流，在河的同一侧有两个村子、，现在河上建一个水电站，使得输电线路最短，试在图中确定水电站的位置（保留作图痕迹并写出作图结果）【解析】如图,作关于河流的对称点，连接交河流于点，连接，.（）如图，等边中，于点，且，为中点，为上一动点，连接、，则的最小值为__________．（直接写出结果）【解析】∵是等边三角形，，，∴,即.连接,线段的长即为的最小值，∵为中点，∴,∴.24．如图，点，在上，，，，与交于点.（）说明的理由；（）试判断的形状，并说明理由.(6分)【解析】（）证明：∵，∴,∴.∴在与中：,∴≌.∴.（）为等腰三角形。证明：∵≌,∴.∴.∴为等腰三角形.25．如图，在中，，平分。求证：。（6分）【解析】∵平分,∴．在和中：,∴≌EMBEDEquation.DSMT4.∴.∴.26．如图，是等腰直角三角形，，直角顶点在轴上，一锐角顶点在轴上。（）如图①，若点的坐标是，点的坐标是，求点的坐标；（2分）（）如图②，若轴恰好平分，与轴交与点，过点作轴于,问与有怎样的数量关系，并说明理由。（2分）（）如图③，直角边在两坐标轴上滑动，使点在第四象限内，过点作轴于，在滑动的过程中，两个结论①为定值；②为定值，只有一个结论成立，请你判断正确的结论加以证明并求出定值。（2分）【解析】（）过点作，∵,.∴.在和中,,∴≌EMBEDEquation.DSMT4.∴.∵点的坐标是，点的坐标是,∴的坐标是,∴,∴,∴点的坐标是。（）证明：延长，交于点，∵轴平分,∴.∵轴,∴.在和中,，∴≌.∴.又∵，，∴，∵平分，∴，，在和中,,∴≌EMBEDEquation.DSMT4.∴,∵,∴.（）①为定值.证明：作.∵,,∴.在和中,,∴≌EMBEDEquation.DSMT4.∴,∵,∴,.∴为定值。3/7_1528800714.unknown_1528806050.unknown_1528988090.unknown_1528997676.unknown_1529082327.unknown_1529089007.unknown_1529091051.unknown_1529092111.unknown_1529092551.unknown_1529092805.unknown_1529092810.unknown_1529092653.unknown_1529092681.unknown_1529092624.unknown_1529092189.unknown_1529092202.unknown_1529092183.unknown_1529091179.unknown_1529091497.unknown_1529091517.unknown_1529091209.unknown_1529091073.unknown_1529090535.unknown_1529090789.unknown_1529091024.unknown_1529090849.unknown_1529090611.unknown_1529090690.unknown_1529090591.unknown_1529089724.unknown_1529090238.unknown_1529089043.unknown_1529087023.unknown_1529087111.unknown_1529088709.unknown_1529087037.unknown_1529082370.unknown_1529086997.unknown_1529082575.unknown_1529082344.unknown_1529081877.unknown_1529081984.unknown_1529082279.unknown_1529082302.unknown_1529082268.unknown_1529081923.unknown_1529081937.unknown_1529081913.unknown_1529081484.unknown_1529081795.unknown_1529081857.unknown_1529081525.unknown_1529081358.unknown_1529081434.unknown_1528997801.unknown_1528989692.unknown_1528989834.unknown_1528993358.unknown_1528995427.unknown_1528996437.unknown_1528996574.unknown_1528996599.unknown_1528996657.unknown_1528996773.unknown_1528996816.unknown_1528996603.unknown_1528996580.unknown_1528996591.unknown_1528996558.unknown_1528996568.unknown_1528996478.unknown_1528996143.unknown_1528996165.unknown_1528995576.unknown_1528995540.unknown_1528995163.unknown_1528995370.unknown_1528995401.unknown_1528995347.unknown_1528995277.unknown_1528995282.unknown_1528995174.unknown_1528993842.unknown_1528994520.unknown_1528995112.unknown_1528995116.unknown_1528994874.unknown_1528995010.unknown_1528994642.unknown_1528993894.unknown_1528993899.unknown_1528994042.unknown_1528993847.unknown_1528993786.unknown_1528993806.unknown_1528993822.unknown_1528993800.unknown_1528993778.unknown_1528993782.unknown_1528993386.unknown_1528992891.unknown_1528993289.unknown_1528993334.unknown_1528993346.unknown_1528993294.unknown_1528993095.unknown_1528993147.unknown_1528992825.unknown_1528992847.unknown_1528992618.unknown_1528992727.unknown_1528992736.unknown_1528992636.unknown_1528992587.unknown_1528989768.unknown_1528989794.unknown_1528989808.unknown_1528989814.unknown_1528989800.unknown_1528989783.unknown_1528989789.unknown_1528989774.unknown_1528989737.unknown_1528989749.unknown_1528989762.unknown_1528989744.unknown_1528989722.unknown_1528989728.unknown_1528989705.unknown_1528988908.unknown_1528989226.unknown_1528989682.unknown_1528989438.unknown_1528989651.unknown_1528989667.unknown_1528989673.unknown_1528989659.unknown_1528989243.unknown_1528989238.unknown_1528988987.unknown_1528989213.unknown_1528989221.unknown_1528989017.unknown_1528988974.unknown_1528988980.unknown_1528988954.unknown_1528988660.unknown_1528988763.unknown_1528988863.unknown_1528988900.unknown_1528988770.unknown_1528988748.unknown_1528988758.unknown_1528988743.unknown_1528988108.unknown_1528988507.unknown_1528988631.unknown_1528988561.unknown_1528988577.unknown_1528988132.unknown_1528988184.unknown_1528983719.unknown_1528986362.unknown_1528987582.unknown_1528987745.unknown_1528988048.unknown_1528988012.unknown_1528987752.unknown_1528987777.unknown_1528987719.unknown_1528987728.unknown_1528987739.un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