初中八年級數(shù)學(xué)下冊期末附答案

精選優(yōu)質(zhì)文檔-----傾情為你奉上精選優(yōu)質(zhì)文檔-----傾情為你奉上專心---專注---專業(yè)專心---專注---專業(yè)精選優(yōu)質(zhì)文檔-----傾情為你奉上專心---專注---專業(yè)新課標(biāo)人教版初中八年級數(shù)學(xué)下冊期末精品試題（附答案）本試卷滿分120分考試時間90分鐘命題人：題號一二三總分核分人得分21222324252627得分評分人選擇題（每小題3分，共36分．下列各題所附的四個選項中，有且只有一個是正確的,請你把答案填在答題卡上）(選擇題答題卡)題號123456789101112答案1．由分式SKIPIF1<0得到分式SKIPIF1<0，所需的條件是（）A．SKIPIF1<0B．SKIPIF1<0C．SKIPIF1<0D．SKIPIF1<02．下列各式的從左到右的變形，正確的是（）A．SKIPIF1<0B．SKIPIF1<0C．SKIPIF1<0D．SKIPIF1<03．已知等腰梯形的的腰等于中位線的長，周長為SKIPIF1<0，則腰長為（）A．SKIPIF1<0B．SKIPIF1<0C．SKIPIF1<0D．以上結(jié)果都不正確4．已知點(diǎn)SKIPIF1<0是雙曲線SKIPIF1<0上一點(diǎn)，則下列各點(diǎn)中在該圖象上的點(diǎn)是（）．A．SKIPIF1<0B．SKIPIF1<0C．SKIPIF1<0D．SKIPIF1<05．在SKIPIF1<0的圖象中，陰影部分面積不為SKIPIF1<0的是（）．6.下列說法中正確的個數(shù)有①對角線互相平分且相等的四邊形是菱形；②有一組對邊平行的四邊形是梯形；③如果四邊形的兩條對角線互相垂直，那么它的面積等于兩條對角線長的積的一半；④如果一個四邊形繞對角線的交點(diǎn)旋轉(zhuǎn)900后，所得圖形與原來的圖形重合，那么這個四邊形是正方形.其中正確的個數(shù)有（）．（A）1個（B）2個 （C）3個 （D）4個7.如圖，已知梯形ABCD中，AD∥BC，AB=CD=AD，AC，BD相交于O點(diǎn)，∠BCD=60°，則下列說法錯誤的是（）．(A)梯形ABCD是軸對稱圖形；(B)BC=2AD；(C)AC平分∠DCB；(D)梯形的面積是△BOC的面積的2倍。ABCDFEOABCD8.ABCDFEOABCD（A）1(B)SKIPIF1<0（C）SKIPIF1<0（D）29．若直角三角形的兩直角邊分別是１和SKIPIF1<0，則斜邊上的高為（）A．SKIPIF1<0B．SKIPIF1<0C．SKIPIF1<0D．SKIPIF1<010.在□ABCD中，AB=5cm，BC=4cm，則□ABCD的周長為cm。（）A．17B．9C．20D．1811．化簡SKIPIF1<0的結(jié)果是A．SKIPIF1<0B．SKIPIF1<0C．SKIPIF1<0D．SKIPIF1<012．已知：一組數(shù)據(jù)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0的平均數(shù)是2，方差是SKIPIF1<0，那么另一組數(shù)據(jù)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0－2，SKIPIF1<0的平均數(shù)和方差分別是（）A．2，SKIPIF1<0B．2，1C．4，SKIPIF1<0D．4，3得分評分人二、填空題（每小題3分，共24分）13．．直線SKIPIF1<0與雙曲線SKIPIF1<0交于點(diǎn)SKIPIF1<0，則SKIPIF1<0；SKIPIF1<0。14.菱形ABCD中，對角線AC與BD相交與點(diǎn)O，點(diǎn)E為AB的中點(diǎn)，若AD=8cm，則OE的長為_________cm。15．已知如圖，在正方形ABCD中，E是CD邊上的一點(diǎn)，連接BE，將△BCE繞點(diǎn)C順時針方向旋轉(zhuǎn)900，得到△DCF，連接EF，若∠BEC=600，則∠EFD的度數(shù)是_________0。SKIPIF1<016．如圖，有一圓柱，其高為12cm，它的底面半徑為3cm，在圓柱下底面A處有一只螞蟻，它想得到上面B處的食物，則螞蟻經(jīng)過的最短距離為________cm。（π取3）17．當(dāng)SKIPIF1<0時，分式方程SKIPIF1<0的解為SKIPIF1<0。18一組數(shù)據(jù)同時減去99，得到新數(shù)據(jù)的平均數(shù)是1，方差是11，極差是21，則原數(shù)據(jù)的平均數(shù)是_____；方差是_____；極差是_____19．如圖所示，將兩條等寬的紙條重疊在一起，則四邊形SKIPIF1<0是SKIPIF1<0，若SKIPIF1<0，SKIPIF1<0，則SKIPIF1<0。20．已知直角三角形兩邊x、y的長滿足SKIPIF1<0，則第三邊的長是_______。得分評分人三、解答題（本大題共7小題，共60分）21．（10分）計算：（1）SKIPIF1<0（2）SKIPIF1<022.（10分）解方程（1）SKIPIF1<0（2）SKIPIF1<023.(6分)如圖，一次函數(shù)SKIPIF1<0的圖象與反比例函數(shù)SKIPIF1<0的圖象交于A、B兩點(diǎn)．（1）利用圖中的條件求反比例函數(shù)和一次函數(shù)的解析式．（2）根據(jù)圖象寫出使一次函數(shù)的值大于反比例函數(shù)的值的x的取值范圍．24．（8分）如圖，在梯形SKIPIF1<0中，SKIPIF1<0，對角線SKIPIF1<0于SKIPIF1<0，若SKIPIF1<0，求梯形的高和梯形的面積。25.(8分)如圖，在平行四邊形ABCD中，SKIPIF1<0分別是邊SKIPIF1<0和SKIPIF1<0上的點(diǎn)且SKIPIF1<0。①線段SKIPIF1<0與線段SKIPIF1<0有怎樣的數(shù)量關(guān)系和位置關(guān)系？并證明你的結(jié)論．（5分）②若AE⊥BC，則四邊形AECF是下列選項中的（）．（3分）A．梯形B．菱形C．正方形D．矩形AABCDFE26（8分）如圖所示，有兩種形狀不同的直角三角形紙片各兩塊，其中一種紙片的兩條直角邊長分別為1和2，另一種紙片的兩條直角邊長都為2．圖a、圖b、圖c是三張形狀、大小完全相同的方格紙，方格紙中的每個小正方形的邊長均為1．請用三種方法將圖中所給四塊直角三角形紙片拼成平行四邊形（非矩形），每種方法要把圖中所給的四塊直角三角形紙片全部用上，互不重疊且不留空隙，三種方法所拼得的平行四邊形（非矩形）的周長互不相等，并把你所拼得的圖形按實際大小畫在圖a、圖b、圖c的方格紙上。要求：（l）所畫圖形各頂點(diǎn)必須與方格紙中的小正方形頂點(diǎn)重合。（2）畫圖時，要保留四塊直角三角形紙片的拼接痕跡。27.（10分）如圖，已知平行四邊形ABCD中，對角線AC、BD交于點(diǎn)O,E是BD延長線上的點(diǎn)，且△AEC等邊三角形．①四邊形ABCD是菱形嗎？并說明你的理由；②若∠AED=2∠EAD，求證：四邊形ABCD是正方形．EECDBAO初二年級數(shù)學(xué)試題答案一、DDABBCDBDB二、13b=1n=31441515度161517m=318100；11；2119菱形SKIPIF1<0205三、21①SKIPIF1<0；②SKIPIF1<022①SKIPIF1<0②x=223①反比例函數(shù)：SKIPIF1<0······································2分一次函數(shù)：y=x-1··········································4分②-1<x<0且x>2············································6分24高6··························································4分面積36··························································8分25①AE與CF平行且相等證明∵四邊形ABCD是平行四邊形∴AF∥CEAD=BC··················································1分又∵DF=BE∴AD-DF=BC-BE即AF=CE··················································3分又∵AF∥CE∴四邊形AECF是平行四邊形∴AE平行且等于CF············································5分②D·······················································3分263分2分3分①是菱形證明：∵△AED是等腰三角形∴∠AEB=∠CEBAE=CE··················································1分在△AED與△CDE中AE=CE∠AEB=∠CEBED=ED(公共邊)∴△AED≌△CDE（SAS）∴AD=CD··················································4分又∵四邊形ABCD是平行四邊形∴四邊形ABCD是菱形··········································5分②證明：∵AB∥CD,AD∥BC∴∠