高二英语人教版必修5课件：Unit1Readingtask

人教课标高二必修5

Unit1更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】ReadingtaskonPage44Unit1Greatscientists更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】What’sEuler’spuzzle?Koningsbergisanislandandthereisariverbreakingitintotwoparts.“SevenBridgesofKonigsberg”andthefamous“Eulerpath”.更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】Peoplewonderediftheycouldwalkaroundthecitybycrossingthesevenbridgeswithoutgoingoveranyofthemtwiceorgoingbackonhimself,butEulerfoundhecouldn’tcrossallthesevenones.ThisisEuler’spuzzle.更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】

Thefirststage

inhisresearchistofindtheproblemthathecouldcrosssixofthebridgeswithoutgoingoveranyofthemtwiceorgoingbackonhimself,buthecouldn’tcrossallseven.HowdidEulerprepareforhisresearch?更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】Thesecondstage

istothinkofamethod:Hedrewamapanduseddotsandlinestosimplifyhisanalysis.Tryingandobservingoverandoveragain,hefoundageneralrule.更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】

Itistopology.Euler’stheoryiscalled“TheEulerpath”,whichisexpressedlikethis:Ifafigurehasmorethantwooddpoints,youcannotgooveritwithoutliftingyourpencilfromthepageorgoingoveralinetwice.Whatarethetheories?更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】SothegeneralrulethatEulerfoundistheevenpointsandtheoddpoints.Lookatthefollowingpictures:更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】更多部编版资料、教材、课件、PPT的免费获取，添加学姐微信【xuejie0627】Conclusion

Euler’stheory

(一笔画)

可以一笔画只有两种情况：

1.没有奇数顶点。

2.只有两个奇数顶点