之前我写了《 科普：用中学数学推导出行星椭圆轨道方程 (4） 》用中学数学推导出了行星的椭圆轨道方程。在 更早的一篇中 ，我写的【我查看了牛顿《自然哲学的数学原理》的行星轨道部分之后，发现牛顿似乎并没有导出轨道的椭圆公式，而是考虑轨道与圆接近的时候，轨道与圆轨道之间的差别。】 牛顿的《 Principia》今天很难读，因为其使用的数学工具过于简陋，没有微积分，代数都很少，基本是用欧几里得几何，数学推导非常繁琐。 今天我翻看了一本专门详细介绍牛顿的《自然哲学之数学原理》的书，名叫《Magnificent Principia》，发现我上面的说法需要纠正一下。 根据这部书，【Newton set himself the following direct problem: Given that a body moves in a conic section with the force center at the focus, what is the nature of the force involved? The inverse problem is then: given an inverse-square-law force, what is the nature of the resulting orbits? Newton gave a formula for solving the direct problem (see section 9.3), and, in this chapter, we have seen the application to conic-section orbits.】【Newton has not shown that when the force is inverse-square law, there are no other orbits than those described as conic sections. Because this is such a pinnacle in the Principia, there should be a proof. Not to give a proof suggests an error of logic: it is just not true that the solution of a problem implies the solution of its converse.】【Even people like Halley, Hooke, and Huygens did not spot this deficiency in Newton's work, but eventually there were rumblings and Johann Bernoulli recognized the problem.】 就是说，牛顿只是算了如果轨道是椭圆（这是开普勒根据观测得到的结果），那么需要的力是平方反比力，但并没有解决反过来的问题，如果力是平方反比力，轨道应该是什么。哈雷、胡克、惠更斯等人都没发现牛顿的这个缺陷，但伯努利发现了。 牛顿后来的辩解是，如果给出初速与位置，那么轨道就唯一确定了，如果某个椭圆轨道符合这个初速与位置，那轨道就是这个轨道。
下面的这些空话套话，讨厌的术语，或者人人都习以为常的废话，最好从你的求职简历中排除。我只翻译了对应词，原因解释请感兴趣的朋友自己看。 10 Words and Terms That Ruin a Resume By Charles Purdy, Monster Senior Editor Your resume needs an update -- that is, if your resume is like that of most people, it’s not as good as it could be. The problem is language: Most resumes are a thicket of deadwood words and phrases -- empty cliches, annoying jargon and recycled buzzwords . Recruiters, HR folks and hiring managers see these terms over and over again, and it makes them sad. Wouldn’t you rather make them happy? It’s time to start raking out your resume, starting with these (and similar) terms. 1. “Salary negotiable” （工资可以商量） Yes, they know. If you’re wasting a precious line of your resume on this term, it looks as though you’re padding -- that you’ve run out of things to talk about. If your salary is not negotiable, that would be somewhat unusual. (Still, don’t put that on your resume either.) 2. “References available by request” （若有要求，可以提供询查） See the preceding comment about unnecessary terms. 3. “Responsible for ______” （负责某项工作） Reading this term, the recruiter can almost picture the C-average, uninspired employee mechanically fulfilling his job requirements -- no more, no less. Having been responsible for something isn’t something you did -- it’s something that happened to you. Turn phrases like “responsible for” into “managed,” “led” or other decisive, strong verbs. 4. “Experience working in ______” （对某项工作有经验） Again, experience is something that happens to you -- not something you achieve. Describe your background in terms of achievements. 5. “Problem-solving skills” （解决问题的技巧） You know who else has problem-solving skills? Monkeys. Dogs. On your resume, stick to skills that require a human. 6. “Detail-oriented” （注重具体细节） So, you pay attention to details. Well, so does everyone else. Don’t you have something unique to tell the hiring manager? Plus, putting this on your resume will make that accidental typo in your cover letter or resume all the more comical. 7. “Hardworking” （工作努力） Have you ever heard the term “show -- don’t tell”? This is where that might apply. Anyone can call himself a hard worker. It’s a lot more convincing if you describe situations in concrete detail in which your hard work benefited an employer. 8. “Team player” （团队精神） See the preceding comment about showing instead of telling. There are very few jobs that don’t involve working with someone else. If you have relevant success stories about collaboration, put them on your resume. Talk about the kinds of teams you worked on, and how you succeeded. 9. “Proactive” （主动性） This is a completely deflated buzzword. Again, show rather than tell. 10. “Objective”（求职目标） This term isn’t always verboten , but you should use it carefully. If your objective is to get the job you’ve applied for, there’s no need to spell that out on your resume with its own heading. A resume objective is usually better replaced by a career summary describing your background, achievements and what you have to offer an employer. An exception might be if you haven’t applied for a specific job and don’t have a lot of experience that speaks to the position you’d like to achieve.
有次我在停车场找停车位，很忙，很多车都在转来转去找地方，好不容易等到一个人要出去，我就排在后面，那车倒车出来后，突然一辆车从另一边乘机钻了进去。我一看是一白人老太太，正得意地朝我笑呢。我哭笑不得。 另一次，我无意中抢了一人的停车位（这很容易发生--当出去的车出去的方向正好挡住了视线），结果那个被我抢位的老美破口大骂。我本来不好意思，准备退出的，他一骂，我干脆就不予理睬，关好车门，扬长而去了。 在高速公路上，有时会遇到愤怒的驾车人。有一次，我正以规定速度行驶，一个黑人女估计自己开小差，差点撞倒我的车后面，结果这女的冲到我旁边，做出各种下流动作，虽然听不见她在说什么，从嘴型看肯定是在骂四字经。 还有一次，在一条崎岖而狭窄的山路上，我正按正常速度行驶，后面一辆BMW上的男子估计想超车，但总是过不去，不断地按喇叭，口中还在嚷嚷的样子。我索性把车停下，按下车窗，回头问: "Sir, is there a problem?" 结果那人支支吾吾，说不出个道道。。。我想也是，谅他也不会用小车撞我的SUV。 由此想到民间保钓。保钓得有一定的技战术。长期以来，倭寇仗着船吨位大，欺凌保钓船。我很久之前就建议租用一艘即将报废的万吨油轮，装满水，接近钓岛时，以每小时5海里的速度缓缓接近登陆。倭寇也就敢撞福建渔民的小船。我就不信倭寇那两三千吨的军舰会自杀性撞击万吨轮。
标签: problem
