湖北省黄冈市2020-2021学年八年级上学期期末数学试题

湖北省黄冈市2020-2021学年八年级上学期期末数学试题）2x）x22x2x22．x．x．．△△∠∠△≌△）∠∠E∠∠D）．325．(p3.14)01．48．(x)xxxx5232326）或或．14x2k）1．212．x2xx11xxxx．．x1．．AOB是OCPNOBNONPM5上一点．已知OM3，ON为DOAPDPMOD）355和73或7．．|a|1a为．22aayAB、l、lOBACABC12OBC．myxnyx2xy6yx2mnmn222．8BM，CMNP点CDNABMPPBN9．1(()4|5|；））2102[(xy)(xy)(xy)]2y2．）2x2．）a4abb9．22//CE，DBCBEC，BDEB，为ADBBCAD．÷+252ABCBACDE在BC，AE．DAE，CACD120，DB∠，EAECDAE若DA用)115abab5a2bkmD、EABC边、ABBD、CE，CDBDCE若AE在CH交BDBAEHEC．HBCFBF90ABBC，,b，ABCC(2，Aa|ab|a4a402a，b．A、C求BACNAMBNMBMA，为ACAMCNCABCD．Bx2x220∴x2x．0D.,:D．32和23xx3.140(p3.14)1．当p0114．．24162(x)xx3226．D°或．Bba2abba22k21x2411121222kxxkxxxx∴x222422．Dxx1x1x2xxx2x．x11xx1DP作于，DERtPDE≌RtPMNDE=MN，．P作于EOB，PN，°DE在和中PDPMPEPNDE在和中PDPMPEPN或．．5时时．°°°．8108a与的n8188108，88-8．0|a|1022aa10a∴a2a20．00∵点P(3,a)关于y轴的对称点为Q(b,2)，∴，b=−3，∴a+b=2+(−3)=−1.故答案为−1.＋OBC．ll、，∵、ABACO12∵BAC°°°°°°°n和xmyxnyx22xy6y2x2mnxymny2x22xy6y2∴m2nmn2n=mnm62=．MMM作MN于接，111NPMMMP11．1MMM作M于111MMC11NPMPNPMPP11MN1°M°1BM8MPNPBN9，∵N11=111M121．y1(()4|5|）2102=9(2)1251812520==[(xy)(xy)(xy)]2y）2[xy(x2xyy)]2y==2222[xyx2xyy]2y2222=[2xy2y]2y=y）2x2）2x29=）a4abb922a2b29=）DBCBEC°AD∵C中DBABECCBDEB，．1．2a21=÷[]2=÷⋅22=1=1=；2a，2a，21=．212C、DAE；C、DAE；°，CACD∵1）21）2111=°222∴DAE°BAC，CACD∵1）21）2111=°22212＋∴12DAE）1．25．.115ab，ab∴5a2bab＝5ab2ab＝525＝5＝．xxx1x1.5x270x180x1.5x901.5xx60x，∠；°中AECDAACBACCB，，2,2ACBb、ACA作yB作xByDBCBE=BD，BB作用，|ab|a24a40ba20∴a2ba20∵a∴a2b0,a202,2AC；A作yB作xB）2x轴y轴°°90ABBC，ABC°中BEABDCEBADBCBABC即，xBB作°°°中CBFBCABMB