2020...85.，Qxyx0x4lg3PQ（Px）x3xx0xx0xx3x4:xRxxp，0p）xR，xx0xRxx0，000000xRxx0，xRxx0，52S22a7aSS，（）nn94n4.）A.1243B.1643C.1233D.1633若3cos25（）25525525535O2mBOmm，B路）A.2B.1003C.2D.1503227如圖所示，平面向量，BRPR）PAQQ關(guān)323cosx,x00nfxfxfx有x，x，kx,x012xx）3n1xx…x0n1當(dāng)kx123n11n3k0且n3tanx當(dāng)當(dāng)x3x345530.fxcos2x9y）34fxsin2xy3fxxfxD.12fxkZk,k12:y2pxp0FF22C于A、BC2AF3中A）以y3213pa0b0，）ab2lglg0bA.若若aab0ab9a115ab2若D.若bab221111466ababa1b23x1lnxxe1gxfx，）xfxA.在Rgx0,在2x0xa2ffelnt1gxtt0D.若fx112xx1e245.xyb22:1ab0F，F(xiàn)CF作xC于A、B兩12a221AB2FFC.122，aaa,Naaxx*mnn1mnmna.2n年月8A，B，，，.3Rhh6R的hV23236.2ACabAcos3sinab2BacabcCCc2222問題：已知Cabcb2A，B，，，，，ac..9Sa11，S.an，nn2anbbn1an.TnnnnP，M，N.；NN點(diǎn).，Oaxbx2xy）y3x，0.xa和b：ytytytx.01，，xyb22:1abFFF1CC2a2212△FPQlP，Q12C:x4ClNA，于M，AQ2.fxeax1aRe，（xfxafx0,.xea2在x2020BBCADABD3334，2110031212B3ABA，2BBB3即.222B3Bcos，B.B0,22263abc1222B又，22cac42acaca224ac故sinAsinBcosC3sinCsinB，sinBCsinBcosC3sinCsinB，sinBcosCcosBsinCsinBcosC3sinCsinB，3cosB3sinBtanB0,B.B36abc3222cosB由，2ac2cac42acaca22843ac843故ac.2acaccosB2abccosC，2accosBbcosC即，2sinAsinCcosBsinBcosC又，2sinAcosBsinBcosCcosBsinCsinBCsinA.120,BBB.3acb1222B由，22cac42acac得a224故aca，qna1qq1qqSqqa，229311343q或，130q，1.n1n2n1b，n1n572n12n1T3n，32n2n113352n12n1Tn，32n1n22222n1T3n3333n13n2222n13n31n1312n14，n1nn2n16T.nABCD，面，D，又PCD，PCD又，為，M，C，又又；1（2DDDA，，DPx，y，zDC11,1,0，DM0,,NAP，AB，DNxyz.22x,y,z設(shè)m11100mxz1m，11100ym1x,y,z設(shè)nxx2xy00n,，x1n2211yz002n2222mn3.PABmn21212231即，22N故.axbxfx32.32bx，fxax則2fxbx4500ax302000axbx0fx2000900013500，ba.x30x20900013500x0,x(x)x3x，2f，x30x020x，tx150t0900013500x則yt2，x150tx150t0t0,3，0150x300x20txt，607500000yt1502x300607500000xtx，t3000,ytyt，0150x300607500000607500000xyt當(dāng)t0或1，0x20x20450030x.0450030.c1a8a2，1，ca2bc3，而ab222x2y21，43x2y211F11,0xtyl431t4y90，22t9Px,yx,y，yy設(shè)，yy1，t4t4112221222yyty111xk，11x12ty3AP1yx2，y6yAP1ty31x4y，令1ty3M16y4,M，1ty316y4,N，2ty320，H66yH,02m2yMHm4,NHm4,設(shè)，，11ty3ty31236yy40m2t12ty3ty31236yy2m40，12tyytyy92121293636yyt429而129ttyytyy92tt921212t4t422429m，或m1m7，2m2m1.）fxea，x00fx在Ra0f，當(dāng)，1fx在R1ea1011a0f又f，e.a0fx0得a，x當(dāng)fxfxx,lnafxxln,a0fx當(dāng)，，，，fxflnaealna1aalna1.a1ln1lngaagaaalna1a0a設(shè)，當(dāng)，0a1ga0gagaa1ga0，當(dāng)a1，gag10aaaa.xx0,fxxex0,1xe1）2對對x2記hx，x1xe1x1xe2xa1mx1xemx0,在0mxxe當(dāng)xxm01mx1，又hx1xmx1xax1；nx0,在xe10當(dāng)且當(dāng)0a1nxex1xxn00exx1.axx2，211110x11x1x2hx，xxx54a10,1hxax1x01110取x，xx2，2000000510,1a0x，hx.xx11x11當(dāng)22000000a的取值范圍為1,.或m1m7，2m2m1.）fxea，x00fx在Ra0f，當(dāng)，1fx在R1ea1011a0f又f，e.a0fx0得a，x當(dāng)fxfxx,lnafxxln,a0fx當(dāng)，，，，fxflnaealna1aalna1.a1ln1lngaagaaalna1a0a設(shè)，當(dāng)，0a1ga0gagaa1ga0，當(dāng)a1，gag10aaaa.xx0,fxxex0,1xe1）2對對x2記hx，x1xe1x1xe2xa1mx1xemx0,在0mxxe當(dāng)xxm01mx1，又hx1xmx1