首页
试卷库
试题库
当前位置:
X题卡
>
所有题目
>
题目详情
已知三元二次型xTAx的平方项系数均为0,并且α=(1,2,-1)T满足Aα=2α。求该二次型表达式;
查看本题答案
包含此试题的试卷
国家统考科目《问答》真题及答案
点击查看
你可能感兴趣的试题
写出一个一根为零并且二次项系数为1的一元二次方程.
已知三元二次型xTAx的平方项系数均为0设α=12-1T且满足Aα=2α.Ⅰ求该二次型表达式Ⅱ求正交
写出一个一元二次方程使有一个根为1并且二次项系数也为1.
已知二次函数fx的二次项系数为a且不等式fx>0的解集为12若fx的最大值小于1则a的取值范围是.
.下列说法正确的是
形如ax
2
+bx+c=0的方程称为一元二次方程
方程(x+2)(x-2)=0是一元二次方程
方程x
2
-2x=1的常数项为0
一元二次方程中,二次项系数、一次项系数及常数项都不能为0
已知三元二次型xTAx经正交变换化为又知A*α=α其中A*为A的伴随矩阵求A及所用正交变换矩阵
一元二次方程x2﹣2x﹣3=0的二次项系数一次项系数常数项分别是
1,﹣2,﹣3
1,﹣2,3
1,2,3
1,2,﹣3
已知二次函数的图象经过0012-1-4三点那么这个二次函数的解析式是__________.
已知三元二次型xTAx的平方项系数均为0设a=12-1T且满足Aa=2a.Ⅰ求该二次型表达式Ⅱ求正交
已知三元二次型xTAx中二次型矩阵A的各行元素之和均为6且满足AB=0其中Ⅰ求正交变换化二次型f为标
一元二次方程4x2+x=1的二次项系数一次项系数常数项分别是
4,0,1
4,1,1
4,1,-1
4,1,0
一元二次方程x2﹣2x﹣3=0的二次项系数一次项系数常数项分别是
1,﹣2,﹣3
1,﹣2,3
1,2,3
1,2,﹣3
已知三元二次型xTAx的平方项系数均为0并且α=12-1T满足Aα=2α求正交变换x=Qy化二次型为
一元二次方程的二次项系数一次项系数常数项分别是
3,2,1
3,-2,1
3,-2, -1
-3,2,1
已知关于x的方程k2-9x2+k+3x=0.1当k为何值时此方程是一元一次方程2当k为何值时此方程是
已知一元二次方程2x2﹣5x﹣6=0其中二次项系数是一次项是常数项是.
已知三元二次型xTAx的平方项系数均为0并且α=12-1T满足Aα=2α若A+kE正定求k的值
一元二次方程3x2-x-2=0的二次项系数一次项系数常数项分别是
3,-1,-2
3,1,-2
3,-1,2
3,1,2
已知三元二次型xTAx的平方项系数均为0并且α=12-1T满足Aα=2α.Ⅰ求该二次型表达式Ⅱ求正交
已知二次函数fx的二次项系数为a且不等式fx>0的解集为12.若fx的最大值小于1则a的取值范围是_
热门试题
更多
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 12
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 18
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 8
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 20
ForhealthinsurancetheUnitedStateshastakentheroadlesstraveled.TheUnitedStatesistheonlyrichcountrywithoutuniversalhealthinsurance.PeopleintheUnitedStatesspendthemostrelyheavilyontheprivatesectorandobtaincarefromtheworld’smostcomplicateddeliverysystem.WhilesomesupportershaveexpressedsatisfactionifnotprideintheseremarkablequalitiesotherscontendthattheUnitedStatesfacesuniquelimitationsinreforminghealthcare.InherexceptionalbookPartingattheCrossroadsAntoniaMaionicomparestheformationoftheU.S.andCanadianhealth-caresystemsfortheyears1930—1960.TheUnitedStatesandCanadaareoftenconsideredthemostsimilarofWesterndemocracies.Theyshareacommonborderarewealthyandhavefederalgovernment.Theirtradeunionsareonlymoderatelypowerfulandtheirpopulationsarediverseandyoung.Neverthelesstheirheath-insurancesystemsarenearlyopposite.TheUnitedStatesreliesonamixofgovernmentplans.TargetedtotheelderlyandindigentandemploymentbasedplanswhichthegovernmentindirectlysupportsCanadaofferspublichealthinsurancetoallqualifiedresidentwiththeprivatesectorprovidingsupplementaryservicesinsomeprovinces.Labororganizationsbecamestrongadvocatesforhealth-insurancereforminbothcountries.Theirimpactpartiallydependedonpoliticalinstitutionsandhowotheractorsparticularlyorganizedmedicinewieldedthem.Canada’sgovernmentalandelectoralsystemsallowedlabortocooperatewithasocialdemocraticpartyintheSaskatchewanprovincewhichestablishedauniversalprogram.TheSaskatchewanprogramdemonstrateduniversalinsurancefeasibilityspurringthedominantLiberalstointroduceanationaluniversalprogram.IncontrasttheU.S.electoralsystemeffectivelyprecludedthird-partyformationforcingorganizedlabortodiluteitshealth-insurancegoalsbecauseitwasoneofmanyinterestsrepresentedbytheDemocraticParty.Maionisuggeststhateconomicvitalityisimportantforthefutureofbothcountries’systemsbuttheprognosisisuncertain.DespiterecentconcernsabouttheCanadiangovernment’sbudgetaryhealthMaionicontendsthatwidespreadsupportprotectsuniversalinsurance.ConverselyMaioniseemspessimisticaboutoptionsforU.S.universalhealthinsurance.Despiteeconomicbuoyancydissensionwilllikelypreventreforms.AlthoughadevastatingeconmnicdownturnwouldmakehealthfinancedifficultineithercountrytheU.S.systemseemsespeciallyvulnerable.Employment-basedinsuranceandMedicarebothrelyonlabormarketattachment.HighchronicunemploymentcouldresultincoveragelossandfinancialdifficultiesforemployerinsuranceandMedicareswellingtheuninsuredpool.Suchacrisiscouldprovideanopeningforuniversalhealthinsurance.InanycasewhethertheUnitedStatesreliesonthepublicorprivatesectorescalatinghealthexpendituresfigureintobudgetofgovernmentcorporationsandfamiliestheU.S.healthcaresystem’sfuturemaydependonAmericanswillingnesstodevotemoreoftheirnationalincometohealthcare.Thepassageismostlikelytobe______.
Mostoftheidlerichsufferunspeakableboredoraasthepriceoftheirfreedomfromdrudgery.AttimestheymayfindreliefbyhuntingbiggameinAfricabutthenumberofsuchsensationsislimitedespeciallyafteryouthispast.46.Accordinglymoreintelligentrichmenworknearlyashardasiftheywerepoorwhilerichwomenmostlykeepthemselvesbusywithinnumerabletriflesofwhoseearth-shakingimportancetheyarefirmlypersuaded. 47.Workisdesirableasapreventiveofboredomfortheboredomamanfeelswhendoingnecessarythoughuninterestingworkisasnothingincomparisonwiththeboredomhefeelswhenhavingnothingtodo.Withthisadvantageofworkanotherisassociatednamelythatitmakesholidaysmuchmoredeliciouswhentheycome.48.Providedamandoesnothavetoworksohardastoimpairhisvigorheislikelytofindfarmorezestinfreetimethananidlemancouldpossiblyfind. Thesecondadvantageofmostpaidworkandofsomeunpaidworkisthatitgiveschancesofsuecessandopportunitiesforambition.Inmostworksuccessismeasuredbyincomeandwhileourcapitalisticsocietycontinuesthisisinevitable.Itisonlywherethebestworkisconcernedthatthismeasureceasestobethenaturalonetoapply.49.Thedesirethatmenfeeltoincreasetheirincomeisquiteasmuchadesireforsuccessasfortheextracomfortsthatahigherincomecanprocure.Howeverdullworkmaybeitbecomesbearableifitisameansofbuihliugupareputationwhetherintheworldatlargeoronlyinone’sowncircle.Continuityofpurposeisoneofthemostessentialingredientsofhappinessinthelongrunandformostmenthiscomeschieflythroughtheirwork. 50.Thesatisfactionofkillingtimeandofaffordingsomeoutlethowevermodestforambitionbelongstomostworkandissufficienttomakeevenamanwhoseworkisdullhappierontheaveragethanamanwhohasnoworkatall.Butwhenworkisinterestingitiscapableofgivingsatisfactionofafarhigherorderthanmererelieffromtedium.Thekindsofworkinwhichthereissomeinterestmaybearrangedinahierarchy.Ishallbeginwiththosewhichareonlymildlyinterestingandendwiththosethatareworthytoabsorbthewholeenergiesofagreatman. 46
Youslipthekeyintotheignitionandcranktheenginetolife.Butbeforeyouputtheearintogearyoutapakeyonthekeyboardmountedbythesteeringwheelandyourneweste-mailflashesuponthewindscreen.Thisseductivesatyriswhatyougetwhenyoucrossaearandaeomputer.Dubbedthenetworkvehieleornet-mobileitmaysooncometoadrivewaynearyouprobablytheonebelongingtoyourrichneighbor.Inanet-mobileamotoristcouldtapintoaregionalroadsystembutalsotomapoutaroutearoundrush-hourtrafficsnags.Driversandpassengerswillbeabletosendandreceivee-mailtrackthelatestsportsscoresorstockquotessurftheWebandevenplayvideogames.Orsoatleastsayanumberofcomputer-industryfirmssuchasMicrosoftSunIBMandNetseape.Themoderncarisalreadyanelectronicshowcaseonwheels.On-boardmicrocomputersimprovefueleconomyandreduceemissions.Theyoperateanti-lockbrakesystemsandonsomeearsevenregulatethefirmnessoftheshockabsorbers.Butmuchofthetechnologyneededtoaddextraisavailablenow.AprototypenetworkvehicleproducedbyaconsortiumofNetseapeSunIBMandDelcoanautomotiveelectronicsfirmbasedinMichiganwasintroducedattherecentannualcomputerindustryshowinLasVegas.Itnotonlyofferedsuchdesktop-eomputer-likeservicesase-mailbutallowedadrivertousethemwithoutlookingawayfromtheroad.Itwasoperatedbyvoicecommandsandprojecteditsdataontothewindscreenusingthesamesortofhead-updisplaysystemfoundinmodernfighterjets.Membersoftheconsortiumthinkareal-worldnetworkvehiclecouldbeinproductioninaslittleasfouryears.Car-makershavealreadybegunrollingoutsomeofthefeaturesfoundontheseprototypenetmobiles.IfthedriverofaGeneralMotorscarequippedwithitsOn-Starsystemlockshiskeyinthecarforexampleanemergencycentrecantransmitadigitalsignaltounlockthedoors.On-staralsocallsautomaticallyforhelpifanaccidenttriggerstheairbags.ToyotaandGeneralMotorsareamongagrowinglistoffirmsofferingsuchin-earnavigationsystems.AndinEuropeBMWandMercedes-Benzrecentlyintroducednavigationhardwarethatcannotonlyplotoutaroutebutalertadrivertotrafficjams.Thein-carnavigationsystemhasallofthefollowingfunctionsEXCEPT______.
已知4元齐次线性方程组的解全是4元方程iix1+x2+x3=0的解求齐次方程组i的解
OnceuponatimeinnovationatProcter&Gambleflowedoneway:fromtheUnitedStatesoutward.WhilethelargeCincinnati-basedcorporationwasnostrangertoforeignmarketsitusuallysoldthemproductsthatwerealreadyfamiliartomostAmericans.ManyJapanesefamiliesforinstanceswaddletheirbabiesinPampersdiapersandlotsofVenezuelansbrushtheirteethwithCrest.AndofcoursecompanyexecutivesassumedAmericansathomewantedthesesamefamiliarredwhite-and-bluebrands.Wemightbuyforeign-madecarsorchocolatesorcameras—buthouseholdcleanersanddetergents.9RecentlyhoweverP&Gbrokewiththislong-standingtradition.ArielaP&GlaundrydetergentwasbornoverseasandisafamiliarsightonstoreshelvesinEuropeandLatinAmerica.NowbilingualpackagesofArielUltraasuper-concentratedcleanerareappearingonsupermarketshelvesinLosAngeles.Ariel’sappearanceintheUnitedStatesreflectsdemographicchangesmakingHispanicsthenation’sfastest-growingethnicgroup.Arielisahitwiththispopulation.InfactmanyMexicanimmigrantslivinginsouthernCaliforniahavebeenimportingArielfromTijuanaMexico.HispaniesknewthisproductandwanteditsaysP&GspokeswomanMarieSalvado.Werealizedthatwecouldn’tconvincethemtobuyourotherlaundrydetergents.P&Ghopesthatnon-HispanicconsumerswillgiveArielatrytoo.Ariel’salreadystrongpresenceinEuropemayprovideaspringboardforthecompanytoexpandintoothermarketsaswell.RecentlyP&GboughtRakonaCzechoslovakia’stopdetergentmaker.ArielcurrentlyatopsellerinGermanyislikelytobeoneofthefastnewbrandstoappearinCzechsupermarkets.AndArielisnottileonlyforeignideathatthecompanyhopestotransplantbacktoitshometerritory.Cinchanall-purposespraycleanersimilartopopularEuropeanproductsiscurrentlybeingtest-marketedinCaliforniaandArizona.TraditionallyAmericanshaveusedseparatecleanersfordifferenttypesofsurfacesbutmarketresearchshowsthatAmericanpreferencesarebecomingmorelikethoseinothercountries.InsidersnotethatthisnewreverseflowofinnovationreflectsmoresweepingchangesatProcter&Camble.ThefirmhashiredmanynewJapaneseGermanandMexicanmanagerswhoviewP&G’sbusinessnotasaone-wayflowofAmericanideasbutatwo-wayexchangewithothermarkets.SaysBonitaAustinoftheinvestmentfinWertheimSchroederWhenyoumetwithP&G’stopmanagersyearsagoyouwouldn’thaveseenasingleforeignface;todaytheycouldevenbeinthemajority.AsProcter&GamblehasfoundtheUnitedStatesisnolongeranisolatedmarket.Americansaremoreopenthaneverbeforetobuyingforeign-madeproductsandtosellingUS-madeproductsoverseas.AccordingtothetextProcter&Gamblehopestotransplantforeignideabacktoitshometerritorybecause______.
Anthropologistscommonlydistinguishthreeformsofmarriage:monogamythemarriageofonemantoonewomanpolygynythemarriageofonemantotwoormorewomenandpolyandrythemarriageofonewomantotwoormoremen.Polygynyandpolyandryareoftenlinkedunderthesingletermpolygamyamarriageofoneindividualtotwoormorespouses.ThoughtherearemanysocietieswhichpermitorevenencouragepolygamousmarriagesitdoesnotfollowinsuchsocietiesthateverymarriedindividualoreventhatamajorityofthemhasmorethanonespouseQuitethecontraryistrueforinmostifnotallofsocalledpolygamoussocietiesmonogamyisstatisticallytheprevailingform.Thereasonforthisisclear:theproportionofmaletofemalebirthsinanyhumansocietyisroughlythesameandifthisproportionismaintainedamongthesexuallymatureapreponderanceofpluralmarriagesmeansthataconsiderablenumberofeithermenorwomenmustremainunmarried.Nosocietycanmaintainitselfundersuchconditions;theemotionalstresseswouldbetoogreattobesurvived.Accordinglyevenwheretheculturalidealsdonotprohibitpluralmarriagesthesemayoccuronanynotablescaleonlysocietieswhereforonereasonoranotheronesexmarkedlyoutnumberstheother.Inshortmonogamynotonlyprevailsinmostoftheworld’ssocietieseitherastheonlyapprovedformofmarriageorastheonlyfeasibleformbutitmayalsoprevailwithinapolygamoussocietywhereveryoftenonlyaminorityofthepopulationcanactuallysecuremorethanonespouse.Inapolygynoushouseholdthehusbandmustsupplyahouseandgardenforeachofhiswives.Thewiveslivewithhiminturncookingandservingfurhimduringtheperiodofhisvisit.Thefirstwifetakesprecedenceovertheothers.Polyandryismuchrarerthanpolygyny.Itisoftentheresultofadisproportionintheratioofmentowomen.Insumpolygamyisnotassofrequentlyindicateduniversallyaresultofhumanimmorality.Itissimplynottrueinthisaspectofeuhureasinmanyothersthatpeoplewhofollowpatternsofculturedeemedimmoralinoursocietyaretherebylackinginmorality.Ouridealandcompulsorypatternofmarriagewhichholdsthatmonogamyistheonlyappropriateformofmarriageisnotsharedbyallpeoplesevenbysomeofthosewhoregularlypracticemonogamy.Inagreatmanysocietiesmonogamyisonlyonepossibleformofmarriagewithpolygynyorpolyandryasperfectlypossiblethoughlessfrequentalternatives.Theauthorbelievesthatpluralmarriagesoccuronsubstantialscalesonlyinsocietiesinwhich______.
Anthropologistscommonlydistinguishthreeformsofmarriage:monogamythemarriageofonemantoonewomanpolygynythemarriageofonemantotwoormorewomenandpolyandrythemarriageofonewomantotwoormoremen.Polygynyandpolyandryareoftenlinkedunderthesingletermpolygamyamarriageofoneindividualtotwoormorespouses.ThoughtherearemanysocietieswhichpermitorevenencouragepolygamousmarriagesitdoesnotfollowinsuchsocietiesthateverymarriedindividualoreventhatamajorityofthemhasmorethanonespouseQuitethecontraryistrueforinmostifnotallofsocalledpolygamoussocietiesmonogamyisstatisticallytheprevailingform.Thereasonforthisisclear:theproportionofmaletofemalebirthsinanyhumansocietyisroughlythesameandifthisproportionismaintainedamongthesexuallymatureapreponderanceofpluralmarriagesmeansthataconsiderablenumberofeithermenorwomenmustremainunmarried.Nosocietycanmaintainitselfundersuchconditions;theemotionalstresseswouldbetoogreattobesurvived.Accordinglyevenwheretheculturalidealsdonotprohibitpluralmarriagesthesemayoccuronanynotablescaleonlysocietieswhereforonereasonoranotheronesexmarkedlyoutnumberstheother.Inshortmonogamynotonlyprevailsinmostoftheworld’ssocietieseitherastheonlyapprovedformofmarriageorastheonlyfeasibleformbutitmayalsoprevailwithinapolygamoussocietywhereveryoftenonlyaminorityofthepopulationcanactuallysecuremorethanonespouse.Inapolygynoushouseholdthehusbandmustsupplyahouseandgardenforeachofhiswives.Thewiveslivewithhiminturncookingandservingfurhimduringtheperiodofhisvisit.Thefirstwifetakesprecedenceovertheothers.Polyandryismuchrarerthanpolygyny.Itisoftentheresultofadisproportionintheratioofmentowomen.Insumpolygamyisnotassofrequentlyindicateduniversallyaresultofhumanimmorality.Itissimplynottrueinthisaspectofeuhureasinmanyothersthatpeoplewhofollowpatternsofculturedeemedimmoralinoursocietyaretherebylackinginmorality.Ouridealandcompulsorypatternofmarriagewhichholdsthatmonogamyistheonlyappropriateformofmarriageisnotsharedbyallpeoplesevenbysomeofthosewhoregularlypracticemonogamy.Inagreatmanysocietiesmonogamyisonlyonepossibleformofmarriagewithpolygynyorpolyandryasperfectlypossiblethoughlessfrequentalternatives.Wecaninferfromthelastparagraphthat______.
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 6
Allmodernhumanoriginatedinsub-SaharanAfricaaccordingtoanewstudyboastedbyitsfoundersasthe"finalblow"againstanopposingviewpoint.Notsofastsaysoneanthropologistwhofindsflawsintheevidence. ThenewstudypublishedintheJuly19issueofthejournalNaturedeliverswhattheresearcherssaycouldbethefinalverdictinsupportofthesinglepoint"OutofAfrica"theory. Manicaandcolleaguestookmultiplemeasurementsofmorethan4500malefossilskullsfrom105populationsaroundtheglobe.TheycombinedtheresultswithdatafromstudiesofglobalgeneticvariationsinhumansfindingthatbothgeneticandskullvariabilitydecreasedwithdistancefromAfrica.SopopulationsinsoutheasternAfricaheldthehighestvariabilitycomparedwithpopulationsinothercountries. Theresultsheldevenwhenthescientistsaccountedforclimatesinceclimateconditionscanleadtochangesinskullfeatures."Inverycoldclimatesyoutendtogenerateaslightlythickerbrowridge.Whetherornotthat’stokeephorribleblizzardsoutofyoureyesIdon’tknow"Amossaid. Paststudiesbasedonskullmorphologyhavebeenweakandhavesupportedbothofthehumanoriginviews. InhisownresearchHawksisfundingthatnaturalselectionhasledtochangesinthousandsofgenesduringonlythepastfewthousandyears. "I’mreallythinkingjusttheoppositeofthispaper"Hawkssaid."Therearedifferencesintheskullbetweenpopulationsincludingtheirvariabilitybutitismostlyduetoveryrecenteffectsandnottheoriginofmodernhumans." "ThemuhiregionalideaisidenticaltotherecentAfricanoriginideaexceptforitspredictionthatEuropeansandAsianswerepartofthesinglepopulationoforiginanddidn’tbecomeextinct." [A]"HumansseemtohavepouredoutofAfricaspreadoutacrosstheworldbutatareallyquiteuniformratesuchthatyougetthislovelygraduallossofdiversity"saidstudyteammemberWilliamAmosoftheUniversityofCambridge. [B]Allmodernhumansoriginatedfromthesameancestorsandtheykeptevolvingasthesocietyadvances.Somespeciesdiedoutbutothersremainedtoliveontheearthwhichisstillimpossibletosolve. [C]Attheendofthedayaresolutiontothe"OutofAfrica"debatemaybeimpossiblehesaid.Mostoftheevidencecanbeinterpretedassupportingbothhuman-originstheories."It’sreallyhardtofindthetwo"Hawkssaid. [D]Thisstudy"addsastronglineofevidencetotheOutofAfricahypothesisusingsuchmorphology"saidpaleontologistWillHarcourt-SmithoftheAmericanMuseumofNaturalHistoryinNewYork.Harcourt-Smithwasnotinvolvedinthecurrentresearch. [E]DebateovertheoriginsofmodernhumanshassimmeredamonganthropologistsforyearswithonetheoryassertingthatHomosapiensmigratedacrosstheworldfromasinglepointinAfrica.TheothertheorystatesthatmultiplepopulationsofHomosapiensindependentlyevolvedfromHomoerectusinregionsbeyondAfrica. [F]TherecentstudywasfundedbytheBiotechnologyandBiologicalSciencesResearchCouncil.Ithasprovidedconclusiveevidenceconcerningtheactualprocessofhumanevolution. [G]"Wehavecombinedourgeneticdatawithnewmeasurementsofalargesampleofskullstoshowdefinitelythatmodernhumansoriginatedfromasingleareainsub-SaharanAfrica"saidleadresearcherAndreaManicaoftheUniversityofCambridge. 41.______42.______43.______44.______45. 44
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 16
OnceuponatimeinnovationatProcter&Gambleflowedoneway:fromtheUnitedStatesoutward.WhilethelargeCincinnati-basedcorporationwasnostrangertoforeignmarketsitusuallysoldthemproductsthatwerealreadyfamiliartomostAmericans.ManyJapanesefamiliesforinstanceswaddletheirbabiesinPampersdiapersandlotsofVenezuelansbrushtheirteethwithCrest.AndofcoursecompanyexecutivesassumedAmericansathomewantedthesesamefamiliarredwhite-and-bluebrands.Wemightbuyforeign-madecarsorchocolatesorcameras—buthouseholdcleanersanddetergents.9RecentlyhoweverP&Gbrokewiththislong-standingtradition.ArielaP&GlaundrydetergentwasbornoverseasandisafamiliarsightonstoreshelvesinEuropeandLatinAmerica.NowbilingualpackagesofArielUltraasuper-concentratedcleanerareappearingonsupermarketshelvesinLosAngeles.Ariel’sappearanceintheUnitedStatesreflectsdemographicchangesmakingHispanicsthenation’sfastest-growingethnicgroup.Arielisahitwiththispopulation.InfactmanyMexicanimmigrantslivinginsouthernCaliforniahavebeenimportingArielfromTijuanaMexico.HispaniesknewthisproductandwanteditsaysP&GspokeswomanMarieSalvado.Werealizedthatwecouldn’tconvincethemtobuyourotherlaundrydetergents.P&Ghopesthatnon-HispanicconsumerswillgiveArielatrytoo.Ariel’salreadystrongpresenceinEuropemayprovideaspringboardforthecompanytoexpandintoothermarketsaswell.RecentlyP&GboughtRakonaCzechoslovakia’stopdetergentmaker.ArielcurrentlyatopsellerinGermanyislikelytobeoneofthefastnewbrandstoappearinCzechsupermarkets.AndArielisnottileonlyforeignideathatthecompanyhopestotransplantbacktoitshometerritory.Cinchanall-purposespraycleanersimilartopopularEuropeanproductsiscurrentlybeingtest-marketedinCaliforniaandArizona.TraditionallyAmericanshaveusedseparatecleanersfordifferenttypesofsurfacesbutmarketresearchshowsthatAmericanpreferencesarebecomingmorelikethoseinothercountries.InsidersnotethatthisnewreverseflowofinnovationreflectsmoresweepingchangesatProcter&Camble.ThefirmhashiredmanynewJapaneseGermanandMexicanmanagerswhoviewP&G’sbusinessnotasaone-wayflowofAmericanideasbutatwo-wayexchangewithothermarkets.SaysBonitaAustinoftheinvestmentfinWertheimSchroederWhenyoumetwithP&G’stopmanagersyearsagoyouwouldn’thaveseenasingleforeignface;todaytheycouldevenbeinthemajority.AsProcter&GamblehasfoundtheUnitedStatesisnolongeranisolatedmarket.Americansaremoreopenthaneverbeforetobuyingforeign-madeproductsandtosellingUS-madeproductsoverseas.WhichofthefollowingistrueaboutAriel
Allmodernhumanoriginatedinsub-SaharanAfricaaccordingtoanewstudyboastedbyitsfoundersasthe"finalblow"againstanopposingviewpoint.Notsofastsaysoneanthropologistwhofindsflawsintheevidence. ThenewstudypublishedintheJuly19issueofthejournalNaturedeliverswhattheresearcherssaycouldbethefinalverdictinsupportofthesinglepoint"OutofAfrica"theory. Manicaandcolleaguestookmultiplemeasurementsofmorethan4500malefossilskullsfrom105populationsaroundtheglobe.TheycombinedtheresultswithdatafromstudiesofglobalgeneticvariationsinhumansfindingthatbothgeneticandskullvariabilitydecreasedwithdistancefromAfrica.SopopulationsinsoutheasternAfricaheldthehighestvariabilitycomparedwithpopulationsinothercountries. Theresultsheldevenwhenthescientistsaccountedforclimatesinceclimateconditionscanleadtochangesinskullfeatures."Inverycoldclimatesyoutendtogenerateaslightlythickerbrowridge.Whetherornotthat’stokeephorribleblizzardsoutofyoureyesIdon’tknow"Amossaid. Paststudiesbasedonskullmorphologyhavebeenweakandhavesupportedbothofthehumanoriginviews. InhisownresearchHawksisfundingthatnaturalselectionhasledtochangesinthousandsofgenesduringonlythepastfewthousandyears. "I’mreallythinkingjusttheoppositeofthispaper"Hawkssaid."Therearedifferencesintheskullbetweenpopulationsincludingtheirvariabilitybutitismostlyduetoveryrecenteffectsandnottheoriginofmodernhumans." "ThemuhiregionalideaisidenticaltotherecentAfricanoriginideaexceptforitspredictionthatEuropeansandAsianswerepartofthesinglepopulationoforiginanddidn’tbecomeextinct." [A]"HumansseemtohavepouredoutofAfricaspreadoutacrosstheworldbutatareallyquiteuniformratesuchthatyougetthislovelygraduallossofdiversity"saidstudyteammemberWilliamAmosoftheUniversityofCambridge. [B]Allmodernhumansoriginatedfromthesameancestorsandtheykeptevolvingasthesocietyadvances.Somespeciesdiedoutbutothersremainedtoliveontheearthwhichisstillimpossibletosolve. [C]Attheendofthedayaresolutiontothe"OutofAfrica"debatemaybeimpossiblehesaid.Mostoftheevidencecanbeinterpretedassupportingbothhuman-originstheories."It’sreallyhardtofindthetwo"Hawkssaid. [D]Thisstudy"addsastronglineofevidencetotheOutofAfricahypothesisusingsuchmorphology"saidpaleontologistWillHarcourt-SmithoftheAmericanMuseumofNaturalHistoryinNewYork.Harcourt-Smithwasnotinvolvedinthecurrentresearch. [E]DebateovertheoriginsofmodernhumanshassimmeredamonganthropologistsforyearswithonetheoryassertingthatHomosapiensmigratedacrosstheworldfromasinglepointinAfrica.TheothertheorystatesthatmultiplepopulationsofHomosapiensindependentlyevolvedfromHomoerectusinregionsbeyondAfrica. [F]TherecentstudywasfundedbytheBiotechnologyandBiologicalSciencesResearchCouncil.Ithasprovidedconclusiveevidenceconcerningtheactualprocessofhumanevolution. [G]"Wehavecombinedourgeneticdatawithnewmeasurementsofalargesampleofskullstoshowdefinitelythatmodernhumansoriginatedfromasingleareainsub-SaharanAfrica"saidleadresearcherAndreaManicaoftheUniversityofCambridge. 41.______42.______43.______44.______45. 42
设f’x在[0+∞上单调减少且证明级数收敛
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 14
计算反常积分
ForhealthinsurancetheUnitedStateshastakentheroadlesstraveled.TheUnitedStatesistheonlyrichcountrywithoutuniversalhealthinsurance.PeopleintheUnitedStatesspendthemostrelyheavilyontheprivatesectorandobtaincarefromtheworld’smostcomplicateddeliverysystem.WhilesomesupportershaveexpressedsatisfactionifnotprideintheseremarkablequalitiesotherscontendthattheUnitedStatesfacesuniquelimitationsinreforminghealthcare.InherexceptionalbookPartingattheCrossroadsAntoniaMaionicomparestheformationoftheU.S.andCanadianhealth-caresystemsfortheyears1930—1960.TheUnitedStatesandCanadaareoftenconsideredthemostsimilarofWesterndemocracies.Theyshareacommonborderarewealthyandhavefederalgovernment.Theirtradeunionsareonlymoderatelypowerfulandtheirpopulationsarediverseandyoung.Neverthelesstheirheath-insurancesystemsarenearlyopposite.TheUnitedStatesreliesonamixofgovernmentplans.TargetedtotheelderlyandindigentandemploymentbasedplanswhichthegovernmentindirectlysupportsCanadaofferspublichealthinsurancetoallqualifiedresidentwiththeprivatesectorprovidingsupplementaryservicesinsomeprovinces.Labororganizationsbecamestrongadvocatesforhealth-insurancereforminbothcountries.Theirimpactpartiallydependedonpoliticalinstitutionsandhowotheractorsparticularlyorganizedmedicinewieldedthem.Canada’sgovernmentalandelectoralsystemsallowedlabortocooperatewithasocialdemocraticpartyintheSaskatchewanprovincewhichestablishedauniversalprogram.TheSaskatchewanprogramdemonstrateduniversalinsurancefeasibilityspurringthedominantLiberalstointroduceanationaluniversalprogram.IncontrasttheU.S.electoralsystemeffectivelyprecludedthird-partyformationforcingorganizedlabortodiluteitshealth-insurancegoalsbecauseitwasoneofmanyinterestsrepresentedbytheDemocraticParty.Maionisuggeststhateconomicvitalityisimportantforthefutureofbothcountries’systemsbuttheprognosisisuncertain.DespiterecentconcernsabouttheCanadiangovernment’sbudgetaryhealthMaionicontendsthatwidespreadsupportprotectsuniversalinsurance.ConverselyMaioniseemspessimisticaboutoptionsforU.S.universalhealthinsurance.Despiteeconomicbuoyancydissensionwilllikelypreventreforms.AlthoughadevastatingeconmnicdownturnwouldmakehealthfinancedifficultineithercountrytheU.S.systemseemsespeciallyvulnerable.Employment-basedinsuranceandMedicarebothrelyonlabormarketattachment.HighchronicunemploymentcouldresultincoveragelossandfinancialdifficultiesforemployerinsuranceandMedicareswellingtheuninsuredpool.Suchacrisiscouldprovideanopeningforuniversalhealthinsurance.InanycasewhethertheUnitedStatesreliesonthepublicorprivatesectorescalatinghealthexpendituresfigureintobudgetofgovernmentcorporationsandfamiliestheU.S.healthcaresystem’sfuturemaydependonAmericanswillingnesstodevotemoreoftheirnationalincometohealthcare.FromthefirstsentencewelearnthattheUnitedStates______.
PartB Directions: Studythefollowingdrawingcarefullyandwriteanessayabout200wordsinwhichyoushould 1describethedrawingbriefly 2interpretitsintendedmeaningand 3giveyourcomment.
Mostoftheidlerichsufferunspeakableboredoraasthepriceoftheirfreedomfromdrudgery.AttimestheymayfindreliefbyhuntingbiggameinAfricabutthenumberofsuchsensationsislimitedespeciallyafteryouthispast.46.Accordinglymoreintelligentrichmenworknearlyashardasiftheywerepoorwhilerichwomenmostlykeepthemselvesbusywithinnumerabletriflesofwhoseearth-shakingimportancetheyarefirmlypersuaded. 47.Workisdesirableasapreventiveofboredomfortheboredomamanfeelswhendoingnecessarythoughuninterestingworkisasnothingincomparisonwiththeboredomhefeelswhenhavingnothingtodo.Withthisadvantageofworkanotherisassociatednamelythatitmakesholidaysmuchmoredeliciouswhentheycome.48.Providedamandoesnothavetoworksohardastoimpairhisvigorheislikelytofindfarmorezestinfreetimethananidlemancouldpossiblyfind. Thesecondadvantageofmostpaidworkandofsomeunpaidworkisthatitgiveschancesofsuecessandopportunitiesforambition.Inmostworksuccessismeasuredbyincomeandwhileourcapitalisticsocietycontinuesthisisinevitable.Itisonlywherethebestworkisconcernedthatthismeasureceasestobethenaturalonetoapply.49.Thedesirethatmenfeeltoincreasetheirincomeisquiteasmuchadesireforsuccessasfortheextracomfortsthatahigherincomecanprocure.Howeverdullworkmaybeitbecomesbearableifitisameansofbuihliugupareputationwhetherintheworldatlargeoronlyinone’sowncircle.Continuityofpurposeisoneofthemostessentialingredientsofhappinessinthelongrunandformostmenthiscomeschieflythroughtheirwork. 50.Thesatisfactionofkillingtimeandofaffordingsomeoutlethowevermodestforambitionbelongstomostworkandissufficienttomakeevenamanwhoseworkisdullhappierontheaveragethanamanwhohasnoworkatall.Butwhenworkisinterestingitiscapableofgivingsatisfactionofafarhigherorderthanmererelieffromtedium.Thekindsofworkinwhichthereissomeinterestmaybearrangedinahierarchy.Ishallbeginwiththosewhichareonlymildlyinterestingandendwiththosethatareworthytoabsorbthewholeenergiesofagreatman. 50
ForhealthinsurancetheUnitedStateshastakentheroadlesstraveled.TheUnitedStatesistheonlyrichcountrywithoutuniversalhealthinsurance.PeopleintheUnitedStatesspendthemostrelyheavilyontheprivatesectorandobtaincarefromtheworld’smostcomplicateddeliverysystem.WhilesomesupportershaveexpressedsatisfactionifnotprideintheseremarkablequalitiesotherscontendthattheUnitedStatesfacesuniquelimitationsinreforminghealthcare.InherexceptionalbookPartingattheCrossroadsAntoniaMaionicomparestheformationoftheU.S.andCanadianhealth-caresystemsfortheyears1930—1960.TheUnitedStatesandCanadaareoftenconsideredthemostsimilarofWesterndemocracies.Theyshareacommonborderarewealthyandhavefederalgovernment.Theirtradeunionsareonlymoderatelypowerfulandtheirpopulationsarediverseandyoung.Neverthelesstheirheath-insurancesystemsarenearlyopposite.TheUnitedStatesreliesonamixofgovernmentplans.TargetedtotheelderlyandindigentandemploymentbasedplanswhichthegovernmentindirectlysupportsCanadaofferspublichealthinsurancetoallqualifiedresidentwiththeprivatesectorprovidingsupplementaryservicesinsomeprovinces.Labororganizationsbecamestrongadvocatesforhealth-insurancereforminbothcountries.Theirimpactpartiallydependedonpoliticalinstitutionsandhowotheractorsparticularlyorganizedmedicinewieldedthem.Canada’sgovernmentalandelectoralsystemsallowedlabortocooperatewithasocialdemocraticpartyintheSaskatchewanprovincewhichestablishedauniversalprogram.TheSaskatchewanprogramdemonstrateduniversalinsurancefeasibilityspurringthedominantLiberalstointroduceanationaluniversalprogram.IncontrasttheU.S.electoralsystemeffectivelyprecludedthird-partyformationforcingorganizedlabortodiluteitshealth-insurancegoalsbecauseitwasoneofmanyinterestsrepresentedbytheDemocraticParty.Maionisuggeststhateconomicvitalityisimportantforthefutureofbothcountries’systemsbuttheprognosisisuncertain.DespiterecentconcernsabouttheCanadiangovernment’sbudgetaryhealthMaionicontendsthatwidespreadsupportprotectsuniversalinsurance.ConverselyMaioniseemspessimisticaboutoptionsforU.S.universalhealthinsurance.Despiteeconomicbuoyancydissensionwilllikelypreventreforms.AlthoughadevastatingeconmnicdownturnwouldmakehealthfinancedifficultineithercountrytheU.S.systemseemsespeciallyvulnerable.Employment-basedinsuranceandMedicarebothrelyonlabormarketattachment.HighchronicunemploymentcouldresultincoveragelossandfinancialdifficultiesforemployerinsuranceandMedicareswellingtheuninsuredpool.Suchacrisiscouldprovideanopeningforuniversalhealthinsurance.InanycasewhethertheUnitedStatesreliesonthepublicorprivatesectorescalatinghealthexpendituresfigureintobudgetofgovernmentcorporationsandfamiliestheU.S.healthcaresystem’sfuturemaydependonAmericanswillingnesstodevotemoreoftheirnationalincometohealthcare.TheSaskatchewanprograminCanadashowsthat______.
In1998consumerscouldpurchasevirtuallyanythingovertheInternet.Bookscompactdiscsandevenstockswere1fromWorldWideWebsitesthatseemedto2almostdailyafewyearsearliersomepeoplehadpredictedthatconsunersaccustomedtoshoppinginstoreswouldbe3tobuythingsthattheycouldnotseeortouch4.Foragrowingnumberoftime-starvedconsumershowevershoppingfromtheirhomecomputerwasprovingtobeaconvenient5todrivingtothestore. Aresearchestimatedthatin1998USconsumerscouldpurchase$7.3billionofgoodsovertheInternetdoublethe1997total.Findingabargainwasgettingeasier6theriseofonlineauctionsandWebsitesthatdidcomparisonshoppingontheInternetforthebest7. Foralltheconsumerinterest8ineyberspaeewasstillalargely9businesshowever.InternetpioneerAmazon.eomwhichbegansellingbooksin1995andlater10intorecordedmusicandvideosposted11of$153.7millioninthethirdquarterupfrom$37.9millioninthesameperiodof1997.Overall12thecompany’slosswidenedto$45.2millionfrom$9.6millionandanalystsdidnotexpectthecompanytoturnaprofit132001.14thegreatlossAmazon.tomhadastockmarketvalueofmanybillionsreflectinginvestors’15aboutthefutureoftheindustry. Internetretailingappealed16investorsbecauseitprovidedanefficientmeansforreachingmillionsofconsumerswithouthavingthecostofoperating17storeswiththeirarmiesofsalespeople.Sellingonlinecarrieditsownriskshowever18somanycompaniescompetingtorconsumers’attentionpricecompetitionwas19andprofit20thinornonexistent. 10
Youslipthekeyintotheignitionandcranktheenginetolife.Butbeforeyouputtheearintogearyoutapakeyonthekeyboardmountedbythesteeringwheelandyourneweste-mailflashesuponthewindscreen.Thisseductivesatyriswhatyougetwhenyoucrossaearandaeomputer.Dubbedthenetworkvehieleornet-mobileitmaysooncometoadrivewaynearyouprobablytheonebelongingtoyourrichneighbor.Inanet-mobileamotoristcouldtapintoaregionalroadsystembutalsotomapoutaroutearoundrush-hourtrafficsnags.Driversandpassengerswillbeabletosendandreceivee-mailtrackthelatestsportsscoresorstockquotessurftheWebandevenplayvideogames.Orsoatleastsayanumberofcomputer-industryfirmssuchasMicrosoftSunIBMandNetseape.Themoderncarisalreadyanelectronicshowcaseonwheels.On-boardmicrocomputersimprovefueleconomyandreduceemissions.Theyoperateanti-lockbrakesystemsandonsomeearsevenregulatethefirmnessoftheshockabsorbers.Butmuchofthetechnologyneededtoaddextraisavailablenow.AprototypenetworkvehicleproducedbyaconsortiumofNetseapeSunIBMandDelcoanautomotiveelectronicsfirmbasedinMichiganwasintroducedattherecentannualcomputerindustryshowinLasVegas.Itnotonlyofferedsuchdesktop-eomputer-likeservicesase-mailbutallowedadrivertousethemwithoutlookingawayfromtheroad.Itwasoperatedbyvoicecommandsandprojecteditsdataontothewindscreenusingthesamesortofhead-updisplaysystemfoundinmodernfighterjets.Membersoftheconsortiumthinkareal-worldnetworkvehiclecouldbeinproductioninaslittleasfouryears.Car-makershavealreadybegunrollingoutsomeofthefeaturesfoundontheseprototypenetmobiles.IfthedriverofaGeneralMotorscarequippedwithitsOn-Starsystemlockshiskeyinthecarforexampleanemergencycentrecantransmitadigitalsignaltounlockthedoors.On-staralsocallsautomaticallyforhelpifanaccidenttriggerstheairbags.ToyotaandGeneralMotorsareamongagrowinglistoffirmsofferingsuchin-earnavigationsystems.AndinEuropeBMWandMercedes-Benzrecentlyintroducednavigationhardwarethatcannotonlyplotoutaroutebutalertadrivertotrafficjams.Anelectronicshowcaseonwheelsprobablymeans______.
计算累次积分
Mostoftheidlerichsufferunspeakableboredoraasthepriceoftheirfreedomfromdrudgery.AttimestheymayfindreliefbyhuntingbiggameinAfricabutthenumberofsuchsensationsislimitedespeciallyafteryouthispast.46.Accordinglymoreintelligentrichmenworknearlyashardasiftheywerepoorwhilerichwomenmostlykeepthemselvesbusywithinnumerabletriflesofwhoseearth-shakingimportancetheyarefirmlypersuaded. 47.Workisdesirableasapreventiveofboredomfortheboredomamanfeelswhendoingnecessarythoughuninterestingworkisasnothingincomparisonwiththeboredomhefeelswhenhavingnothingtodo.Withthisadvantageofworkanotherisassociatednamelythatitmakesholidaysmuchmoredeliciouswhentheycome.48.Providedamandoesnothavetoworksohardastoimpairhisvigorheislikelytofindfarmorezestinfreetimethananidlemancouldpossiblyfind. Thesecondadvantageofmostpaidworkandofsomeunpaidworkisthatitgiveschancesofsuecessandopportunitiesforambition.Inmostworksuccessismeasuredbyincomeandwhileourcapitalisticsocietycontinuesthisisinevitable.Itisonlywherethebestworkisconcernedthatthismeasureceasestobethenaturalonetoapply.49.Thedesirethatmenfeeltoincreasetheirincomeisquiteasmuchadesireforsuccessasfortheextracomfortsthatahigherincomecanprocure.Howeverdullworkmaybeitbecomesbearableifitisameansofbuihliugupareputationwhetherintheworldatlargeoronlyinone’sowncircle.Continuityofpurposeisoneofthemostessentialingredientsofhappinessinthelongrunandformostmenthiscomeschieflythroughtheirwork. 50.Thesatisfactionofkillingtimeandofaffordingsomeoutlethowevermodestforambitionbelongstomostworkandissufficienttomakeevenamanwhoseworkisdullhappierontheaveragethanamanwhohasnoworkatall.Butwhenworkisinterestingitiscapableofgivingsatisfactionofafarhigherorderthanmererelieffromtedium.Thekindsofworkinwhichthereissomeinterestmaybearrangedinahierarchy.Ishallbeginwiththosewhichareonlymildlyinterestingandendwiththosethatareworthytoabsorbthewholeenergiesofagreatman. 48
Anthropologistscommonlydistinguishthreeformsofmarriage:monogamythemarriageofonemantoonewomanpolygynythemarriageofonemantotwoormorewomenandpolyandrythemarriageofonewomantotwoormoremen.Polygynyandpolyandryareoftenlinkedunderthesingletermpolygamyamarriageofoneindividualtotwoormorespouses.ThoughtherearemanysocietieswhichpermitorevenencouragepolygamousmarriagesitdoesnotfollowinsuchsocietiesthateverymarriedindividualoreventhatamajorityofthemhasmorethanonespouseQuitethecontraryistrueforinmostifnotallofsocalledpolygamoussocietiesmonogamyisstatisticallytheprevailingform.Thereasonforthisisclear:theproportionofmaletofemalebirthsinanyhumansocietyisroughlythesameandifthisproportionismaintainedamongthesexuallymatureapreponderanceofpluralmarriagesmeansthataconsiderablenumberofeithermenorwomenmustremainunmarried.Nosocietycanmaintainitselfundersuchconditions;theemotionalstresseswouldbetoogreattobesurvived.Accordinglyevenwheretheculturalidealsdonotprohibitpluralmarriagesthesemayoccuronanynotablescaleonlysocietieswhereforonereasonoranotheronesexmarkedlyoutnumberstheother.Inshortmonogamynotonlyprevailsinmostoftheworld’ssocietieseitherastheonlyapprovedformofmarriageorastheonlyfeasibleformbutitmayalsoprevailwithinapolygamoussocietywhereveryoftenonlyaminorityofthepopulationcanactuallysecuremorethanonespouse.Inapolygynoushouseholdthehusbandmustsupplyahouseandgardenforeachofhiswives.Thewiveslivewithhiminturncookingandservingfurhimduringtheperiodofhisvisit.Thefirstwifetakesprecedenceovertheothers.Polyandryismuchrarerthanpolygyny.Itisoftentheresultofadisproportionintheratioofmentowomen.Insumpolygamyisnotassofrequentlyindicateduniversallyaresultofhumanimmorality.Itissimplynottrueinthisaspectofeuhureasinmanyothersthatpeoplewhofollowpatternsofculturedeemedimmoralinoursocietyaretherebylackinginmorality.Ouridealandcompulsorypatternofmarriagewhichholdsthatmonogamyistheonlyappropriateformofmarriageisnotsharedbyallpeoplesevenbysomeofthosewhoregularlypracticemonogamy.Inagreatmanysocietiesmonogamyisonlyonepossibleformofmarriagewithpolygynyorpolyandryasperfectlypossiblethoughlessfrequentalternatives.Amarriagebetweenseveralmenandwomenshouldbecalled______.
已知A是3阶矩阵αii=123是3维非零列向量若Aαi=iαii=123令α=α1+α2+α3证明αAαA2α线性无关
设在某一时间段内进入某大型超市的顾客人数X服从参数为A的泊松分布且每一顾客购买A种商品的概率为p假定各顾客是否购买A种商品是相互独立的求进入该超市的顾客购买A种商品的人数Y的概率分布及Y的期望EY
热门题库
更多
高考历史
国家统考科目
香港法概论
反间谍法
__学
合同法
证据学
民事诉讼法学
民法学
刑法学
消费者权益保护法
法理学
竞争法
国际公法
国际经济法
农村政策法规