填空题级数的收敛域为________．

填空题已知α 1 =(2，3，4，5) T ，α 2 =(3，4，5，6) T ，α 3 =(4，5，6，7) T ，α 4 =(5，6，7，8) T ， 则r(α 1 ，α 2 ，α 3 ，α 4 )=______.

填空题设η为非零向量，A=，为方程组AX=0的解，则a=________，方程组的通解为________．

填空题已知f(x)是微分方程满足f(1)=0的特解，则=______．

填空题设y=e 3-x ，则dy| x=3 =______．

填空题设f(x)为奇函数，且f"(1)=2，则=________．

填空题线性方程组有解的充分必要条件是______．

填空题四阶行列式的值是________．

填空题设，则k=________．

填空题 若方程组无解则

填空题设f(x，y)连续，且，其中D由y=0，y=x2及x=1围成，则f(x，y)=________．

填空题微分方程y"一4y=e 2x 的通解为y=______．

填空题设三阶矩阵A，B满足关系A-1BA=6A+BA，且A=，则B=________

填空题设函数y=y(x)由方程y=1一xey确定，则=________。

填空题[A]Hemphasbeencultivatedbymanyculturesforthousandsofyears.Itproducesfibrewhichcanbemadeintopaper,fuel,oils,textiles,food,andrope.Formanycenturies,itwasessentialtotheeconomiesofmanycountriesbecauseitwasusedtomaketheropesandcablesusedonsailingships;colonialexpansionandtheestablishmentofaworld-widetradingnetworkwouldnothavebeenpossiblewithouthemp.Nowadays,ships'cablesareusuallymadefrom'wireorsyntheticfibres,butscientistsarenowsuggestingthatthecultivationofhempshouldberevivedfortheproductionofpaperandpulp.Accordingtoitsproponents,fourtimesasmuchpapercanbeproducedfromlandusinghempratherthantress,andmanyenvironmentalistsbelievethatthelarge-scalecultivationofhempcouldreducethepressureonCanada'sforests.[B]MuchofCanada'sforestryproductiongoestowardsmakingpulpandpaper.AccordingtotheCanadianPulpandPaperAssociation,Canadasupplies34%oftheworld'swoodpulpand49%ofitsnewsprintpaper.Ifthesepaperproductscouldbeproducedinsomeotherway,Canadianforestscouldbepreserved.Recently,apossiblealternativewayofproducingpaperhasbeensuggestedbyagriculturalistsandenvironmentalists:aplantcalledhemp.[C]Inrecentyears,twomajormovementsforlegalizationhavebeengatheringstrength.OnegroupofactivistsbelievesthatALLcannabisshouldbelegal--boththehempplantandthemarijuanaplant--andthattheuseofthedragmarijuanashouldnotbeanoffense.Theyarguethatmarijuanaisnotdangerousoraddictive,andthatitisusedbylargenumbersofpeoplewhoarenotcriminalsbutproductivemembersofsociety.Theyalsopointoutthatmarijuanaislesstoxicthanalcoholortobacco.[D]However,thereisaproblem:hempisillegalinmanycountriesoftheworld.Thisplant,sousefulforfibre,rope,oil,fuelandtextiles,isaspeciesofcannabis,relatedtotheplantfromwhichmarijuanaisproduced.[E]Theotherlegalizationmovementisconcernedonlywiththehempplantusedtoproducefibre;thisgroupwantstomakeitlegaltocultivatetheplantandsellthefibreforpaperandpulpproduction.Thissecondgrouphashadamajortriumphrecently:in1997,Canadalegalizedthefarmingofhempforfibre.Forthefirsttimesince1938,hundredsoffarmersareplantingthiscrop,andsoonwecanexpecttoseepulpandpaperproducedfromthisnewsource.[F]Inthelate1930s,amovementtobanthedrugmarijuanabegantogatherforce,resultingintheeventualbanningofthecultivationnotonlyoftheplantusedtoproducethedrug,butalsoofthecommercialfibre-producinghempplant.AlthoughbothGeorgeWashingtonandThomasJeffersongrewhempinlargequantitiesontheirownland,anyAmericangrowingtheplanttodaywouldsoonfindhimselfinprison--despitethefactthatmarijuanacannotbeproducedfromthehempplant,sinceitcontainsalmostnoTHC(theactiveingredientinthedrug).[G]Everysecond,1hectareoftheworld'srainforestisdestroyed.That'sequivalenttotwofootballfields.AnareathesizeofNewYorkCityislosteveryday.Inayear,thataddsupto31millionhectares--morethanthelandareaofPoland.Thisalarmingrateofdestructionhasseriousconsequencesfortheenvironment;scientistsestimate,forexample,that137speciesofplant,insectoranimalbecomeextincteverydayduetologging.InBritishColumbia,where,since1990,thirteenrainforestvalleyshavebeenclear-cut,142speciesofsalmonhavealreadybecomeextinct,andthehabitatsofgrizzlybears,wolvesandmanyothercreaturesarethreatened.Logging,however,providesjobs,profits,taxesforthegovernmentandcheapproductsofallkindsforconsumers,sothegovernmentisreluctanttorestrictorcontrolit.

填空题若二次型的正、负惯性指数都是1，则a=______．

填空题若∫f(x)dx=arctan x+C，则f(x)=______。

填空题设z=sin(xy)，则dz=______。

填空题设λ 1 ，λ 2 ，λ 3 是三阶矩阵A的三个不同特征值，α 1 ，α 2 ，α 3 分别是属于特征值λ 1 ，λ 2 ，λ 3 的特征向量，若α 1 ，A(α 1 +α 2 )，A 2 (α 1 +α 2 +α 3 )线性无关，则λ 1 ，λ 2 ，λ 3 满足______

填空题∫sec 2 5xdx=______．