湖南省怀化市2019-2020学年中考数学五模考试卷含解析

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170⚪ὃYGᦪḄH?Z⌕ὃY\]^_᦮ᦪᢣᦪ^ᱯ$Ḅᦪ%bcde᪷ᔜ2hiV&'⚪Ḅᐵ*.20.(1)y=-^x12+3^x+S(2)জS=j(஻L5)2+?,mm=5nSoᨬᜧ%qঝstᩩvḄV;Fᐳᨵx2ᙶ᪗ᑖ{|ᱏ((8),F(1,4),~(1,6+2)(|,6-2«),2ூ'᪆௃ூᑖ᪆௃4(1)AஹCVᙶ᪗ᐭᱥy=-gx2+bx+c,ᓽNᱥḄ'᪆Qq(2)জᐜᵨm⊤5QEḄK5Ḅ☢SᐵmḄᦪqঝᑏ5stᩩvḄFVḄᙶ᪗ᓽN⌕¡ᑏ.ூO'௃c=8'.(1)AஹCVᙶ᪗ᐭᱥ4“¢¢——x36+6b+c=09'.]3,c=844ᱥḄ'᪆Q|y=--x2+yx+8;(2)জ3OA=8,OC=6,:AC=[Q4?+0c2=[()7QEAB3;VQ¤QE_LBC¥EV¦§|sinNACB=—=—QCAC5•QE_3**10-m-©3r.QE=y(10-m),113ஹ3,..S=—,CP»QE=—m—x(z10-m)=------m2+3m#22510]133315ঝ•.•S=—CPQE=—mx—(10-m)=------m2+3m=-------(m-5)2+—22510102.•.mm=5nSoᨬᜧ%qᙠᱥ
IᙠVF,AFDQ|443•••ᱥḄ'᪆Q|y=--x2+yx+8Ḅ
|x=-,DḄᙶ᪗|(3,8),Q(3,4),3mNFDQ=90஺nFi(p8),

183NFQD=90஺ᑣFz(V4),3NDFQ=90஺³F(',n),¦ljFD2+FQ2=DQ2,44ᓽV+(8-n)2+—+(n-4)2=16,99#'n=6+—,2F3(-,6+^^-),F4(->6-),2222¶·ᩩ¹ḄFᐳᨵXFᙶ᪗ᑖ½Fi(—,8),Fz(-,4),F3(6+^^-),F4(■-,6-).222222)⚪ὃ.ᦪḄ¾ᔠ¯ᵨ¿ÀᐸzÁKᑮḄÂᨵÃᱥ7Ḅ᪆=Ḅ£ÅÃᱥ7ḄᨬÆÇÂᔜᙢzὃḄÊ:Ë⚪ÌÍᦪjDᔠᦪÎÏÐḄᵨÎÑ⌕ÒÓÔqÕÖz᫏⚪.21.(2)ØÙÚ᪆o(2)DᡂÛᳮᵫÚ᪆o(3)2Ýᡈ2Ý.ூ᪆௃ூᑖ᪆௃(2)ᵫNDPC=NA=NB=90஺"#NADP=NBPC,ᓽ"ØᑮßADPs^BPC,ᯠ§ᵨàám2jḄឋ9ᓽ"vw⚪o(2)ᵫNDPC=NA=NB=O"#NADP=NBPC,ᓽ"ØᑮßADPs^BPC,ᯠ§ᵨàám2jḄឋ9ᓽ"vw⚪o(3)âDãDE_LABÖE,᪷CÇῪm2jḄឋ9"#AE=BE=3,᪷Crs3ᳮ"#DE=4,ᵫ⚪"#DC=DE=4,ᑣᨵBC=2-4=2.᧕ØNDPC=NA=NB.᪷CADBC=APBP,æ"£utḄÆ.ூ௃:(2)᝞I2,VZDPC=ZA=ZB=90°,

19.,.NADP+NAPD=90஺ZBPC+ZAPD=90°,/.ZAPD=ZBPC,/.ADP^ABPC,.ADAP-------fBPBCAADBC=APBP
(2)DADBC=APBPçᡂÛ;ØÙ'᝞I2,VZBPD=ZDPC+ZBPC,XVNBPD=NA+NAPD,:.NDPC+NBPC=NA+NAPD,VZDPC=ZA=O,.*.ZBPC=ZAPD,è'é=4=0,/.ªADP^ABPC,ADAP•■----=-----,BPBCAADBC=APBP
(3)᝞`IâDãDEJ_ABÖE,VAD=BD=2,AB=6,AE=BE=3.\0£=^52-32=4,:Dᙊ{DCḄᙊABàᑗ,.\DC=DE=4,ABC=2-4=2,VAD=BD,•NANB,XVZDPC=ZA,

20.♦.NDPC=NA=NB,ᵫ(2)(2)Ḅíî#ADBC=APBP,èAP=t,BP=6-t,.'.t(6-t)=2x2,t=2ᡈt=2,•••tḄÆ2Ýᡈ2Ý.ூ(௃)⚪ὃ.ᙊḄ¾ᔠ⚪.22.(1)ØÙÚ᪆o(2)EM=4
(3)sinZEOB=^l.4ூ᪆௃ூᑖ᪆௃(1)AஹC,EஹBïðñ◤⌕£ußAMC:AEMBàáᓽ"£uD᪷Cᙊᕜ23ᳮ"4uóÑḄx¯2àÇᓽ"#AAMC^AEMB
(2)᪷Cᙊᕜ23ᳮDᔠrs3ᳮ"4uECḄ¤᪷Côᩩ¹4uAMஹBMḄ¤ᯠ§Dᔠ(1)ḄDõö᧕æ"£uEMḄ¤o(3)âEãEF_LAB,ᚖ·F,øâãùú72m2jDᔠôᩩ¹:(1)(2)ᡠ£ḄÆ"4uRtAEOFᔜiḄ¤᪷C┦2m2GᦪḄ3ýþ"£#sin/EOBḄÆ.ூ௃(1)ØÙ'ACஹEB,᝞I1,VZA=ZBEC,ZB=ZACM,/.AMC^AEMB
(2)'TDC஺OḄ.".ZDEC=90°,.,.DE2+EC2=DC2,VDE=V15CD=8,ÿEC
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21.,.BM=2,AM=6,VAM»BM=EM»CM=EM(EC-EM)=EM(7-EM)=12,EM>MC,.EM=4(3)EEFLAB,ᚖ
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13<2,83456Ḅ᦮ᦪ
1,2,1.ூ᪆௃ூᑖ᪆௃ᐜ=>3456Ḅ7+ᓽ@=A83456Ḅ᦮ᦪ.ூB௃%—3(x-2)<4জᵫজA+x>l,ᵫঝA+x<2.ᡠQ3456Ḅ7
1SXV2,83456Ḅ᦮ᦪ
1,2,1.ூ௃⚪ὃḄ-RᐗRT3456U=RᐗRT3456Ḅ᦮ᦪ+=345ḄVᐳ+⌕⍳ZQ[\ᑣ:_ᜧabᜧ+_cabc+cᜧᜧcde+ᜧᜧcc3.

2224.(1):9O¯'᪆q(2):9O¯'᪆q(3)1.ூ'᪆௃ூᑖ᪆௃(Dᑭᵨ±LḄឋ³c´VḄNᑭᵨAAS:µ¶q(2)ᵫ(1)NAF=BD,µᔠᩩvNAF=DC,ᑣN:9xADCF|±LxºᑭᵨḄឋ³N:AD=CD,N:xADCF|»q(3)¼DF,N:xABDF|±LxᑣNDFḄᑭᵨ»Ḅ☢½QN-ᫀ.ூO'௃(1):9.VAF/7BC,...NAFE=NDBE,TE&ADḄ´V.♦.AE=DE,ᙠ4AFE^ADBE´NAFE=NDBE

23•.•fg&ADCF-h&,11S®ADCF=_AC'DF=-x4x5=l.22ூ௃⚪i⌕ὃh&Ḅឋ*Uᑨ(+ᑭᵨᐰ4%&Ḅឋ*mAAF=CD-⚪Ḅᐵ,+noh&☢qV5Ḅrᵨ.25.(1)Bs᪆t(2)(u+1).3ூ᪆௃ூᑖ᪆௃(1)᪷wxy(ᳮ@AABḄ{+ᓽOMḄ|}+᪷w_ᡠ~Ḅᙊᕜ@ABDᑖNABO
(2)᪀ᑗAE,᪷wᱯḄ%ᦪ@ANOAB=30஺+ᑖEFAFḄ{+@AEḄᙶ᪗.ூB௃(1)•A(73,0)"B(0,-1),.,.OA=V3,OB=1,*'•AB==2,TAB-஺MḄ|}+.•G)MḄ|}
2,VZCOD=ZCBO,ZCOD=ZCBA,.,.ZCBO=ZCBA,ᓽBDᑖNABO
(2)᝞+AAE_LABE,BDḄ{E,EEFJ_OAF,ᓽAE-ᑗ,OR1C•ᙠR3ACB+tanZOAB=——=-==—,OAy/33.\ZOAB=30o,VZABO=90°,AZOBA=60°,:.ZABC=ZOBC=-ZABO=30°,2:.OC=OB*tan30°=lx4=33.\AC=OA-OC=^I,3

24:.ZACE=ZABC+ZOAB=60°,.".ZEAC=60°,/.ACE-4g%&+.*.AE=AC=^^,3.,.AFAE=+EF=3AE=1232/.OF=OA-AF=^I,3...EḄᙶ᪗
(2+1).3ூ௃⚪ᙊḄᔠ⚪+ὃxy(ᳮஹᙊᕜ(ᳮஹ4g%&Ḅᑨ("ឋ*QU%ᦪ4.no>-⚪Ḅᐵ,.26.(1)᫑DC"|ABḄ¢-6.0km(2)£ᙠ¤Aᙢᑮ§Bᙢ@¨\ᩭª«Ḅ¬-4.1km.ூ᪆௃ூᑖ᪆௃(1)CᔣABᚖ᪀%&+=>ᚖ¯Ḅ{°ᓽ@t(2)DᔣABᚖ+ᯠ²᪷w%&=>AD,CBḄ{+³´=>£ᙠ¤Aᙢᑮ§Bᙢ@¨\ᩭª«Ḅ¬.ூB௃(1)CH_LABH,᝞ᡠµ+VBC=12km,NB=30°,

25.CH=gBC=6km,BH=6gkm,ᓽ᫑DC¥ABḄÀÁ&6.0km2
¤DM_LABVM,᝞ᡠ,•᫑DCAB±LCH=6km,.".DM=CH=6km,VZDMA=90°,NB=45°,MH=EF=DC,DM_6_y^6/.AD=sin45km,AM=DM=6km,V.,•ÊᙠËAᙢᑮÎBᙢNÏPᩭÑÒḄÓ<&.AD+DC+BC
-AM+MH+BH
=AD+DC+BC-AM-MH-BH=AD+BC-AM-BH=60+12-6-6g=6+60-6Ôa4.1km,ᓽÊᙠËAᙢᑮÎBᙢNÏPᩭÑÒḄÓ<&4.1km.ூVW௃×ØÙ᪀Û᪷ÜᐵÝ'&'-0⚪Ḅᐵ*.627.OWkSlÞk#l.ூ'᪆௃ூᑖ᪆௃᪷Ü]⚗Ýᦪà\ஹáâeᦪà_c᪷Ḅᑨ{QªKåᓽN5ᐵkḄRᐗR]Qç'èᓽN5kḄo%ê.ூO'௃'.,•,ᐵxḄRᐗ]e0,k-1ð,A=V2^
2-4x3k-l
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26⚪ὃ᪷Ḅᑨ5ஹ¶T᪷5QURᐗ¶T·Ḅ(¸+᪷w¶T⚗!ᦪº»ஹ¼½·ᦪº¾U᪷Ḅᑨ5AK),ᑡ>ᐵkḄRᐗRT3456-⚪Ḅᐵ,.ÀÁ>()Ã+Rᐗ¶T·ᨵÅÆ3#4ḄÇᦪ᪷tÀA=0Ã+Rᐗ¶T·ᨵÅÆ#4ḄÇᦪ᪷tÀÁ<()Ã+Rᐗ¶T·ÈᨵÇᦪ᪷.

27