北京市通州區(qū)2020-2021學(xué)年八年級上學(xué)期期末數(shù)學(xué)試題

北京市通州區(qū)2020-2021學(xué)年八年級上學(xué)期期末數(shù)學(xué)試題）72.154（）)x1x(）19491259．．．．423）1122ABCABC）xm=m+x1111且D1且4D為OC．如圖，AOB30OB上一點，且CPD點OAPCP）．2．．23．4324a10a．a(chǎn)mm1+．2m112m1.3a2a2b40bb4.Rt△ABC，B6，BC8．ADBAC交邊BCDBD．，10AB，ABACBD32E，F(xiàn)AB4AFBECEDFCEDF5△ACEBDFABCC，30BAABM，1，M，CP2APBCD．①是ABCCM，ACMS△DAC:S1:4；△ABCDABADB1213438．AC，BABC中，ABD在BCCDC，D求a22a112a1a2a14=．42ACDABE交FCDAE交DCGH△ACGABF．5面6050Rt△ABCBRt△ABCD為BC將6ABCCD2，BD82222333x1x2，x1x132x，x1x21x1x111(x1)2x1221；x1x1x1x1x1x1x2x211(xx11②1．xx1x1x1x1a1a22a1a1a2a12a，abba1Rt△ABCABACCAB，DBAEABDECDEACEFCDCBG．FCDA與GGB，C..D.77①1428574=222.151.01001000100001.Dx..D.95種5959.A4231122．B．、B1，．．．CPDPC.PDCDQD''是'DD則PDPD'PDPCPDPC'PQPDPCCD''OD'OD,AODAOB30OD''DODAODAOB60''DOD'DDODOD,ODDDODODD60'''''點為OCDDDODDC'DCDCDD''又DCDCDDODD60'''CDDDCD30''ODCODDCDD603090'''123RtOCD''2'2PC23即PDPCPD.Pπ．（57或）4x16x5x，1．a(chǎn)1令0a.aa10aa(a1)01或a0a0aa11...mm12m11.=2m12m131313.13==9．．.1a2.ba20a2b40∵，b40a2b42a22∴1.b4x，41∴=，4，．3ACD作DEABAE,BDDERtCDE.ACAEDD作DEADBAC12BADEADBAEDADADBADEAD和在BADEAD(AAS)AEAB6,DEBDABC，681022在AB2BC2設(shè)BDxx,CEACAE1064,CDBCBD8x則DE在RtCDE2DECE224(8)xCD22x23BD3x..ABDNABD作C作CM3AB45CMAMDNBN3CEDF47,NFDFDN7CMMECE2222337AEBFACE和BE②AFAFEFBEEFAEBFAB45,BD32又ACEBDFSASCEBDFACEBCADFADB③CADBAB又CDACBD32ASAACEBDFCEDF5CM4,NFDFDN4MECE2222,DFBDCECAMEAM,NFBNEMFNBNMEAMBNNFAB10又AMENFM2BF347AE由ACEBDFSSS...1AM,PCPMACAP又APACPAMP(SSS)CAPMAP則BACADABC90,30ACBBBACACBB180AM又ACACM1BAC302CDRtACDADBBMAPMADBCBDCDADCDCDCDCD111SSCD,S222:S1:3DACABCBDADDABCAPCAD則ADBCADACB3090120..．3．.23432223223223..．D．D70,DAC.BACBABAC在ACBB70ADCACDC在DACDADCADC在ACB為DACDACB701D.2.1．2a.(a1a2a2a(a2aa21a(a2aa2(a1)a1aa1211.2將a2a2.+2?4=2?2??2==是1==．2.AB,CB,DACEABAC.ACDABEACAB,CB,DACEABDACDAEEABDAEEACDABGACFABCBACGABFACAB在和GACFAB.3025(x5)x6050.(x5)xx5x60x50(x10x250xx則525530x3025..x和RtABC設(shè)AB.與ACCDADADBDABACCDBDABx設(shè)ABCD2,BD6AC26x,BCCDBD8AC4x在RtABCABBCAC222x8(x4)28x2x222xx6611S6822ABC故ABC.AB324）a02或a．）1）a0，，，2a22a1a12a21.a1ba1a122(a33）1；a2a2a2a22a12(a1)33）2a12a1a1a13當(dāng)a11aa1為3a1，30故，，，24；a22a12(a12(aa1122）2(a1)ba1a1a1a11當(dāng)a，ba11a為111a02.故a或a.）CDAG）GB2AD.DAAEEFCD、；ABCE作GHGHDCAFEDHEGRtBHGADHGGB2HG.DAAEEFCD、）CDAGAC,CAB90ABCABCBA45CBABEG為又G①RtDEF在②BEGFED②-①由得CDA；G）GB2ADABCE作GHGHDEACCDCE,DAAE設(shè)DCAECAABCACB45ACBDCA45在在GCFCFG(45)又ECBACBECA45CGFECBEGCECDHEGFED,FEDADC90,DCAADC90DCAFEDHEGDACGHECDADCAGEH在與EGHCDEGADHGRtBHGGBHABC22..）CDAGAC,CAB90ABCABCBA45CBABEG為又G①RtDEF在②BEGFED②-①由得CDA；G）GB2ADABCE作GHGHDEACCDCE,DAAE設(shè)DCAECAAB