初中數(shù)學(xué)競賽教程

m（n0,m,nn②0③a(a0)|a(|0,0)①②aa2a(a0)③。．m1m）已知兩數(shù)a、b互為相反數(shù)，c、d互為倒數(shù)，x的絕對值是2，求x(ab)d(a)b(。22006|ab||ab|）a、b2a2ababbcca,,有3bccaabb0，，5.1，ab,abaab。.c||||||三個有理數(shù)a,b,cXab的積為負(fù)數(shù)，和為正數(shù)，且則|a||b||c|132若a,b,c|ab||ca|1|ca||ab||bc|20072007|a|a0|a|ab|a、b①2a0|a2||a2||x|x2|若|x5||x27xf(x)|x|x2||x|x|f(x)求|ab(ab1)ab1與2.|a||b||c|abc0abcx|(x(x|x2||x4|①②③④237970.716.62.20.73.31173118111()111．11111111))()23419962323423213141n21222S2131412n21n221234n4.S24816與22nn.1114287013020811222））1335991012abab2(2ab)3(ab)52ababx2y523x6y42113ba2ababab2abqx1Px31qxx1Px31x(2A7B)x(3A8B)8xBx.(1x)(1x)abxcxdxabcd223mm10m2m2322y5x9xy3x3nxymy72ymn222當(dāng)50(2ab)214ab22xy若a,b,cxyZabbccammn15,mnn6mmn2n2222abcabc1aba1bcb1acc1ab1N11abMN，。1a1b1a1bx10x32x1x2.xyzKKyzxzxya3,b4,c5554433a,b,c2aa504a12a9a2432xb3xb3(a2)xb3，(a2)xb3a2a22kxmxnkx21m、nKx36(3x1)axaxaxaaaaaaa3.若554541054321012mx3x1x1(79)m20072m2.x(2k1)x6Kx(m1)x(m1)x80200(mx)(x2m)m22xxxx20067.122334200620078.當(dāng)ax|x2||x5|a）84.1132部A6部AAn.點(diǎn)2133456nn1n…2O3456、On角1233n1n2n…2On角213453nn1n…2ABM∵M(jìn)1∴AMBMAB22，2P1）1221BABAC．2B）.1個2個3個4個1C,C是2()個個個個aa()1是）2:∠,:EA:,,:FA.,An°n(n2)°46米）8米米c0a0,b0、xy.k）2ab13a8.32x23y113ab30.9b1.2）3x25y130.9x8.3．y1.2x10.3．y2.2x6.3x10.3．y0.2．y2.2452x:y21xy453x5y33xyax2y1a3xy3x2y1m2xmy2.若若且。若且。2x76x3x9，像axb0a0（axb0a0（若xaxaxbxaxbxbxabxaxbxaxbbb＞a）a.0002m5xm5x2x3x50mmxxx84x1m）m．m3．m3．m3．m32xx1．x32a）xxa4115211a5211521152aaa．．．．4444x2ya1、2xy1.axyxy2a1.12xmx1m2yaxy2a10x3y12、xy且.axa1a2a5和a22BBAxAByy與xx甲乙AB克克克克111234..E的C點(diǎn)P°°°））°°．CDADEGABBECFP第2第1D.；.AACEEFPNMBDBFCDAC和P在Q在APEDF1QB2.C,QCPQtAB.QP.CD,是C作B作交A；D求.FBCEClBlCElBE為交；.ABDCDABEDC.E,.CBEAD和EBααBββ與DBBBEEFAAACCCFD求.A到BCDE.D是，交交；AFEBCD....1＝2FAED312BCDECAB和BEDFAC于于EDBAFCAEOF.BDC21223121P以P點(diǎn)P點(diǎn)EBD是B作交0交于．00.D在F在＝xD00B、EFD1求NM2AABC.PBC°．ADBC實(shí)數(shù)2若則xaaaa＝aax若xaa＝3a．pqq3，a2nnaa．m152m．x為y．y2a4b2a3b42a2bb()1．012.2aa2b3b0a．b5250求．若babb123n若a為1721是9abbab38，25?16，)??，．5個??(2個3個4個ab3232＝么．＝＝5ab1P．50．yx2y＝b3a5b2a3bS＝p1aaa(a)a(ab)abaaaaa0)a(a0)．．．．0pmnmnmnmnnnnmnmnap24若nn.24222mn，mn.5(2x)4(x)x3n2n332nxm3x6，x3nm2n222m1m2m3b，c9a，c））ab4c，，c22yyxy(nn1)122n2(abc)2010cabcdab，cd，cadb5432...ababab.⑵ab2a2abb2222⑶abc2abc2ab2acbc⑷abaabbab2222233⑸ab3aababb3223abab則ab.22求xy.44若ab2ab2求abab的值，22若y求xy.3322abcabbcac.222若2xkx3被2x1求k.323xmxnx42x5x6＝＝.322xxaxbxcx13＝.432.x2pxq.1m9n229y.xy6x10y34022b.aabb102222cabc.|2a4||b2|(abac22222x2a）2個4個6個8個⑴⑵4x4xy4y3x4y9z12yz22222⑶abab6⑷(xx2)(x3)(x1⑸6y19y102AA若BBBBAAMBBMAAM，(M0)BBM.ababccacadbcbd；cbdacacbdbdacacadbdbdbc；aanbn()nnbx2x2x．x22x1x1x1x()x2x322且33，3且1(xxx1x．112412211x1x1x1xx2x