三元二次型$f(x_{1},x_{2},x_{3})=frac{1}{2}(x_{1}-x_{2})^{2}+frac{1}{2}(x_{2}-x_{3})^{2}+frac{1}{2}(x_{1}-x_{3})^{2}$是正定的,因为它可写作$frac{1}{2}y_{1}^{2}+frac{1}{2}y_{2}^{2}+frac{1}{2}y_{3}^{2}.$
因为把它写作$frac{1}{2}y_{1}^{2}+frac{1}{2}y_{2}^{2}+frac{1}{2}y_{3})^{2}.$时，所做替换$y_{1}=x_{1}-x_{2}，y_{2}=x_{2}-x_{3}，y_{3}=x_...
Cross-cultureUnderstandingonBusinessWeliveinaglobalvillage,buthowwelldoweknowandunderstandthecross-cultureonbusiness?MaybeweassumethatthewidespreadunderstandingofEnglishlanguagemeansacorrespondingunderstandingofEnglishcustoms.However,itmightnotbenecessarilythecase.Ifwewanttohavegoodbusiness,wemusthavethecross-cultureunderstandingonbusiness.Herearesometipsforyoutopayattentionto:1.EyeContactInmanyWesterncountries,includingtheUnitedStates,apersonwhodoesnotmaintain“goodeyecontact”isregardedasbeingslightlysuspicious.Americansunconsciouslyassociatepeoplewhoavoideyecontactasunfriendly,insecure,untrustworthy,inattentiveandimpersonal.However,incontrast,Japaneseadultslowertheireyeswhenspeakingtoasuperior,agestureofrespect.InThailandyoushouldclaspyourhandstogetherandloweryourheadandyoureyeswhenyougreetsomeone.LatinAmericanculture,aswellassomeAfricancultures,suchasNigeria,havelongerlookingtime,butprolongedeyecontactfromanindividualoflowerstatusisconsidereddisrespectful.IntheUS,itisconsideredrudetostare–regardlessofwhoislookingatwhom.Incontrast,thepoliteEnglishmanistaughttopaystrictattentiontoaspeaker,tolistencarefully,andblinkhiseyestoletspeakerknowheorshehasbeenunderstoodaswellasheard,whileinPakistanyoumustn’twinkforit’soffensive.2.TimeofArrivalImagineyouhavemadeanappointmentatthreeo’clock.Whattimeshouldyouexpectyourforeignbusinesscolleaguestoarrive?Ifthey’reGerman,they’llberightontime.Ifthey’reAmerican,they’llprobablybe15minutesearly.Ifthey’llbeBritish,they’llbe15minuteslateandyoushouldallowuptoanhourfortheItalians.3.AtMealandDrinkingTimeTheBritisharehappytohavebusinesslunchanddiscussbusinessmatterswithadrinkduringthemeal;theJapaneseprefernottoworkwhileeating.Lunchisatimetorelaxandgettoknowoneanother,andtheyrarelydrinkatlunchtime.TheGermansliketotalkbusinessbeforedinner.However,incontrast,theFrenchliketoeatfirstandtalkafterwards.Theyhavetobewellfedandwateredbeforetheydiscussanything.Andyoushouldn’tsitdowninacaféuntilyou’veshakenhandswitheveryoneyouknowinFrance.InRussiayoumustmatchyourhostsdrinkfordrink,ortheywillthinkyouareunfriendly;inAmericayoushouldeatyourhamburgerwithbothhandsandasquicklyasyoucan.Youshouldn’ttrytohaveaconversationuntilitiseaten;intheMiddleEastyoumustneverusethelefthandforeating,drinking,smokingorgreeting.Also,youshouldtakecarenottoadmireanythinginyourhost’shome.Theywillfeelthattheyhavetogiveittoyou.Thereareothersuggestionsoncross-cultureunderstandingonbusinessthatmighthelpyouwithyourbusiness.Onlyafewhavebeenmentionedhere.Beforeyougotoacountryonbusiness,youshouldhavetolearnsomethingmoreaboutherculture.WheninRome,doastheRomansdo.Choosethebestanswerforthefollowingquestions.2)WhichofthefollowingisnottrueabouttheBritishaccordingtothetext?
一个栈的进栈序列为1,2，……，n,通过一个栈得到出栈序列p1,p2,……,pn(p1,p2,……,pn是1,2，……，n的一种排列)。若p1=3，则p2可能取值的个数是()。