初二上册数学期中考试试卷(附答案)

1.()ABCD2.AB=AD△ABC≌△ADC()A.\BAC=\DACB.\BCA=\DCAC.CB=CDD.\B=\D=90◦3.()A.a(ab)=a2abB.(2ab)2+a2b=4abC.2ab
3a=6a2bD.(a1)(1a)=a214.()A.B.C.D.5.AB=CDAD=BCOADEBCF()A.4B.5C.6D.76.Rt△ABC\ACB=90◦\A=50◦ACBA′CD\A′DB=()A.40◦B.30◦C.20◦D.10◦7.(23)20031:52002(1)2004()A.23B.32C.23D.328.BC=EFACDF1AB=DE2\ABC+\DFE=90◦3\ABC=\DEF()A.1B.2C.3D.09.x2+6x+k2k()A.3B.3C.3D.910.△ABCABBCCA203040△ABCS△ABO:S△BCO:S△CAO()A.1:1:1B.1:2:3C.2:3:4D.3:4:511.\ACB=60◦PC=12MNCBPM=PNMN=3CM()A.3B.3:5C.4D.4:512.△ABC\ABC=45◦CD?ABDBE\ABCBE?ACECDFDH?BCHBEG①BD=CD②AD+CF=BD③2CE=BF④AE=BG()A.①②B.①③C.①②③D.①②③④13.P(a+2;3)Q(1;b+1)yab=14.△ABCAB=AC=10DEABABDACE△BEC17BC=15.2018220172019=16.A(1;2)B(5;5)C(5;2)E△ACE△ACBE17.△ABC3△BDC\BDC=120◦D60◦ABMACNMN△AMN18.△ABC3cmPQABABBC1cm=sPBPQt=△PBQ19.(1)(3x2y)2
(15xy3)(9x4y2)(2)(2a3)2(1a)2(3)(2+x)(2x)+(x1)(x+5)x=3220.ABCDAB=CBAD=CDACBDOOE?ABOF?CBEFOE=OF21.△ABCAB=CB\ABC=90◦FABEBCAE=CF(1)△ABE≌△CBF(2)\CAE=25◦\BFC22.A(3;2)B(4;3)C(1;1)(1)△ABCy△A1B1C1(2)C1C1(3)△A1B1C1(4)yPPB+PC23.ABCDAD∥BCEABDECBFGBC\GDF=\ADF(1)△ADE≌△BFE(2)EGEGDF24.ABxyB(0;1)\BAO=30◦(1)AB(2)AB△ABEOAMNABADDBD=OE(3)2DEABFFDE12345678910ABCBCDACCC1112DC12.∵CD?AB\ABC=45◦)△BCD)BD=CD①Rt△DFBRt△EFC∵\DBF=90◦\BFD\DCA=90\EFC\BFD=\EFC)\DBF=\DCA∵\BDF=\CDA=90◦BD=CD)△DFB≌△DAC(ASA))BF=ACDF=AD∵CD=CF+DF)AD+CF=BD②Rt△BEARt△BEC∵BE\ABC)\ABE=\CBE∵BE=BE\BEA=\BEC=90◦)Rt△BEA≌Rt△BEC)CE=AE=12AC∵BF=AC)CE=12AC=12BF③CG∵△BCD)BD=CDDH?BC)DHBC)BG=CGRt△CEG∵CGCE)CECG∵CE=AE)AEBG④13.214.715.116.(1;5)(1;1)(5;1)17.6∵△BDC\BDC=120◦)\BCD=\DBC=30◦∵△ABC3)\ABC=\BAC=\BCA=60◦)\DBA=\DCA=90◦ABFBF=CNDF△BDF△CDN8:BF=CN;\FBD=\DCN;DB=DC;)△BDF≌△CDN(SAS))\BDF=\CDNDF=DN∵\MDN=60◦)\BDM+\CDN=60◦)\BDM+\BDF=60◦△DMN△DMF∵8:DM=MD;\FDM=\MDN;DF=DN;)△DMN≌△DMF(SAS))MN=MF=MB+BF=MB+CN)△AMNAM+AN+MN=AM+MB+CN+AN=AB+AC=618.12AP=tcmBQ=tcm△ABCAB=BC=3cm\B=60◦)BP=(3t)cm△PBQBP=3tBQ=t△PBQ\BQP=90◦\BPQ=90◦\BQP=90◦BQ=12BPt=12(3t)t=1(s)\BPQ=90◦BP=12BQ3t=12tt=2(s)t=1st=2s△PBQ19.(1)(3x2y)2
(15xy3)(9x4y2)=9x4y2
(15xy3)(9x4y2)=15xy3:(2)(2a3)2(1a)2=4a212a+91+2aa2=3a210a+8:(3)(2+x)(2x)+(x1)(x+5)=4x2+x2+4x5=4x1:x=32=4321=61=5:20.∵△ABD△CBD8:AB=CB;AD=CD;BD=BD;)△ABD≌△CBD(SSS))\ABD=\CBD)BD\ABC∵OE?ABOF?CB)OE=OF21.(1)∵\ABC=90◦)\ABC=\CBF=90◦Rt△ABERt△CBF∵8:AE=CF;AB=CB;)Rt△ABE≌Rt△CBF(HL)(2)∵AB=CB\ABC=90◦)\CAB=\ACB=45◦∵\CAE=25◦)\BEA=45◦+25◦=70◦∵Rt△ABE≌Rt△CBF)\BFC=\BEA=70◦22.(1)△A1B1C1(2)(1;1)(3)132S=35121512231223=132(4)BC1yPP23.(1)AD∥BC\ADE=\BFEEABAE=BE△ADE△BFE8:\ADE=\BFE;\AED=\BEF;AE=BE;△ADE≌△BFE(AAS)(2)EGDFEGDFEG\GDF=\ADE\ADE=\BFE\GDF=\BFE1△ADE≌△BFEDE=FEGEDFGEDF24.(1)∵Rt△ABO\BAO=30◦)AB=2BO=2(2)OD∵△ABE)AB=AE\EAB=60◦∵\BAO=30◦OAMNABADD)\DAO=60◦)\EAO=\NAB∵DO=DA)△ADO)DA=AO△ABD△AEO∵8:AB=AE;\EAO=\NAB;DA=AO;)△ABD≌△AEO(SAS))BD=OE(3)EH?ABH∵AE=BE)AH=12AB∵BO=12AB)AH=BORt△AEHRt△BAO8:AH=BO;AE=AB;)Rt△AEH≌Rt△BAO(HL))EH=AO=AD∵\EHF=\DAF=90◦△HFE△AFD8:\EHF=\DAF;\EFH=\DFA;EH=AD;)△HFE≌△AFD(AAS))EF=DF)FDE