数学建模习题解答-杨启帆

Dothefollowingthreemainpoints:1findouttheweak.Reviewprocessistosumuptheknowledgeontheonehand,maketheknowledgemorecoherentsystemandregularity,butalsoletthestudentsthemselves,looksupthedeficiencies.So,weteacherstounderstandthestudents'knowledgeofthesituationpriortothereview,studentsnotonlyfoundwidespreaddeficiencies,butalsosomeshortcomings,forthesewelldesignedprograms,reasonablearrangementoftime,thisreviewismoretargetedandmoreeffective.Forexample,youcandesignaformforinvestigation,understandingstudents'weaknessesineachknowledge,putitasareviewofkey,combinedwiththeproblemoftextbookstoreview,bothtoavoidcastinganettihaizhanshu,andimprovetheefficiencyofreview.2,goodcollation.Throughsixyearsofstudy,studentsinthebasics,readingmethod,exercises,andsoalreadyhaveacertaindegreeofaccumulation,thereviewstage,teachersshouldknowhowtoguidethestudentstolabeltheaccumulation,process,formasystemofknowledgenetworks.Exercisesforstudentstoberepresentative,fine,complete,tolive,andearnestlydoaproblemlearningamethod,classofpasswastogettimeefficientreviewresults.3,payattentiontouse.Theaccumulationofknowledgeisultimatelytouse,therefore,reviewthesituationandlifesituationtobecreatedinavarietyoflanguages,guidestudentsonthebasisofthepreviousaccumulationofknowledgetousetothemaximum,andreallyapplywhattheyhavelearned.Second,reviewthecontentandstrategyofthefirstpart:thebasics(a)1,reviewthemainpointsofHanyuPinyinisabletoreciteandwritedownthealphabetofHanyuPinyin;accuratespellingpronunciation(afterreadingcacuminal,nasalsound,light,andretroflexsounds),thecorrectwriteconsonants,vowelsandsyllables.2,.maintypesaccordingtotheorderofthealphabetofHanyuPinyinalphabeticalorder;fillintheappropriateuppercaseandlowercaseletters;seephoneticwritingwords;pinyintowritesentenceswithdottoselectthecorrectpronunciationoftheword;tobringsomeinitialconsonantsorvowels,wordselection.Second,themaintypesofwords(1)Rubywrittenwords;(2)tobringWordtoselectthecorrectpronunciation;(3)useasequencerandradicalcharacterlookupmethod无论是统筹推进“五位一体”总体布局，还是全力推进全面建成小康社会进程，乃至实现“两个一百年”奋斗目标，都需要不忘初心，继续前行。部分数学建模习题解答【杨启帆主编】第一章第5题一个男孩和一个女孩分别在离家2km和1km且方向相反的两所学校里上学，每天同时放学后分别以2km/h和1km/h的速度步行回家。一只小狗以6km/h的速度由男孩奔向女孩，又从女孩处跑向跑回男孩处，如此往返的奔跑，直至回到家中。问小狗总共奔波了多少路程？解：由于男孩、女孩与小狗跑的时间一样，所以把时间设为t，则有2t+1t=3，得到t=1h。所以小狗跑了6km/h*1h=6km。第一章10题一位探险家必须穿过一片宽度为800km的沙漠，他仅有的交通工具是一辆每升汽油可行驶10km的吉普车．吉普车的油箱可装10升汽油。另外吉普车上可携带8个可装5升汽油的油桶，也就是说，吉普车最多可带50升汽油(最多能在沙漠中连续行驶500km)。现假定在探险家出发地的汽油是无限充足的．问这位保险家应怎样设计他的旅行才能通过此沙漠？他要通过沙漠所需的汽油最少是多少升？为了穿越这片800km宽的沙漠，他总共需要行驶多少公里路程。总共要花费多少升的汽油?思路：1、若沙漠只有500公里或者更短，这时很简单，一次搞定。2、若沙漠有550km，怎么办？需要保证的是：车到了离沙漠终点还有500km的地方，能恰恰加满油且不会有多余。方案可为：600-550＝50，从起点处加5*3(升)＝15升油，开出50km，设一加油站，存下5升，剩下5升刚好使得汽车返回起点。再在起点处加满50升油，到加油站时，只乘45升了，把存放在那儿的5升油加上。则可跑出沙漠。（这样共加油15＋50＝65，总路程为150+500＝650km）3、再看2的情况，符合这种情况的沙漠的最大距离是多少呢：答案是500*（1+1/3）公里。即在起点准备100升油，第一次装50升，跑了500/3公里后存放50*1/3升油，然后返回起点，这时车里的油也正好用完，然后再在起点处装50升，跑了550/3公里后，车内剩下（50*2/3）升油，再加上存放的50*1/3升油，恰好为50升油，则可跑出沙漠。4。当沙漠的距离超过了500*（1+1/3）km（但又超过得不多）又当如何？这时我们可以把前面的500*（1+1/3）km看成一段整体，需要保证的是：在距离沙漠终点500*（1+1/3）km处恰恰有100升油（由3的分析可知）。怎么来保证呢，我们假设沙漠的距离只比500*（1+1/3）多了1公里，因为汽车的容量是50升，所以100升油最少从起点运3次油才能满足。除了3次装油，还有两次折回，所以往返正好有5次，这5次能保证的距离是500/5，所以这时我们又把沙漠的距离延伸到了：500*（1+1/3+1/5），起点应该储备150升油。5。当沙漠的距离超过了500*（1+1/3+1/5）km，要保证在距离沙漠终点500*（1+1/3+1/5）km的地方有150升油。综上所述：总有某一个值k,使得fdis=500*（1+1/3+1/5+…+1/(2k-1)）800，但500*(1+1/3+1/5+…+1/(2k-1)+1/(2k+1)）800，应该在起点准备多少油呢？这时多了一小段出来，按情形2的分析，在起点准备的油应当是：（(800-fdis)/油耗）*往返次数+k*50。经计算：fdis=766.66,k=3,故应准备的油应为：（(800–766.66)/10）*7+3*50＝173.338。第一章11题如果你有一个3L的桶和5L的桶，问如何才能准确地称出4L的水？如果你要的不是4L而是别的数量，你又该怎么办？解：准确称出4L水的方法：先把3L的桶装满水，倒入5L的桶中，再把3L的桶装满，Dothefollowingthreemainpoints:1findouttheweak.Reviewprocessistosumuptheknowledgeontheonehand,maketheknowledgemorecoherentsystemandregularity,butalsoletthestudentsthemselves,looksupthedeficiencies.So,weteacherstounderstandthestudents'knowledgeofthesituationpriortothereview,studentsnotonlyfoundwidespreaddeficiencies,butalsosomeshortcomings,forthesewelldesignedprograms,reasonablearrangementoftime,thisreviewismoretargetedandmoreeffective.Forexample,youcandesignaformforinvestigation,understandingstudents'weaknessesineachknowledge,putitasareviewofkey,combinedwiththeproblemoftextbookstoreview,bothtoavoidcastinganettihaizhanshu,andimprovetheefficiencyofreview.2,goodcollation.Throughsixyearsofstudy,studentsinthebasics,readingmethod,exercises,andsoalreadyhaveacertaindegreeofaccumulation,thereviewstage,teachersshouldknowhowtoguidethestudentstolabeltheaccumulation,process,formasystemofknowledgenetworks.Exercisesforstudentstoberepresentative,fine,complete,tolive,andearnestlydoaproblemlearningamethod,classofpasswastogettimeefficientreviewresults.3,payattentiontouse.Theaccumulationofknowledgeisultimatelytouse,therefore,reviewthesituationandlifesituationtobecreatedinavarietyoflanguages,guidestudentsonthebasisofthepreviousaccumulationofknowledgetousetothemaximum,andreallyapplywhattheyhavelearned.Second,reviewthecontentandstrategyofthefirstpart:thebasics(a)1,reviewthemainpointsofHanyuPinyinisabletoreciteandwritedownthealphabetofHanyuPinyin;a