Now Isaac Newton and/or Joseph Raphson figured out how to do this kind of thing for all differentiable functions.
既然牛顿和拉复生已经,指数了如何解这种可导函数,因此我们就不用太担心了。
Successive approximation, Newton-Raphson was one nice example, but there's a whole class of things that get closer and closer, reducing your errors as you go along.
逐渐逼近,牛顿迭代是一个很好的例子,随着你不断的时行下去,你会不断的离结果越来越近,逐渐地减少误差。
It's one thing to plug in all the numbers and say, "I know Newton's laws and I know how they work."
我们平时只是把数字代进公式,然后说,"我懂牛顿定律,也知道怎么使用"
It's really amazing that what Newton did in the case of gravity was to find the expression for this.
这一点非常神奇,牛顿在引力方面的研究,只是为了找出这个的表达式
There, Newton doesn't tell you what forces are going to be acting on a body in a given situation.
在式子里,牛顿没有告诉你,在给定条件下,有哪些力,作用在物体上
Newton is not going to come and tell you what force the spring will exert when it's pulled by some amount.
牛顿不会过来告诉你,弹簧被拉伸一定量时会产生多大的力
You divide and you find it's 9 and you say, "Okay, I know what to do with Newton's laws."
除一下,会得到 9,然后你说,"好了,我会用牛顿定律了"
In fact, until we do electricity and magnetism the next semester, everything's going to be based on just the laws of Newton.
其实,在下学期学习电磁学之前,所有的内容都是基于牛顿定律的
Suppose Newton comes to you and says, "I have this great law, but I don't want to publish it under my name.
假如牛顿对你说,"我发现了这个伟大的定律,但我不想以我的名义发表
But we get tired of saying that long expression, so we're going to call that a Newton, right?
但我们不想说得这么复杂,所以把这个单位称为"牛顿",对吧
So, Newton did not ever tell you what the expression for force is in a given context.
牛顿从来也没有告诉过你,在这种情况下力的表达式
In fact, my program crashes because I end up trying to divide by zero, a really bad thing. Hint: if you implement Newton's method, do not make your first guess zero.
我下一步都没法开始,实际上,我的程序会崩溃,因为我试着去除0了,真糟糕,提示你:如果你想用牛顿的方法,第一个猜想数别设为0。
The point of Newton is, two things in the Law of Inertia, which one may think is trivial.
牛顿的观点是,惯性定律分两部分,可能有人觉得这种分法无关紧要
The great discovery that Galileo and Newton made is that you don't need a force for a body to move at constant velocity.
伽利略和牛顿的伟大发现就是,物体不需要力来维持匀速运动
But Newton's law is-- You see, you've got to go back and wipe out everything you know.
但牛顿定律是,如你所知的,你必须回到过去,忘掉你所知道的一切
You have to be careful that this first law of Newton is not valid for everybody.
大家需要注意的是,牛顿第一定律并非所有情况都适用
Except for electromagnetism, the basics of mechanics, which is the motion of Billiard balls and trucks and marbles and whatnot, was set up by Newton.
除电磁学外,力学的基础,也就是台球,卡车,弹球以及其它小玩意儿的运动原理,都是由牛顿建立起来的
It's the 10 Newtons acting on it, because I know the 10 Newton is pushing me and I'm going to feel it even if I'm here.
他们认为这 10 牛的力作用在了物体上,因为这个力在推着物体前进,物体能感觉到的,即使没有直接接触
Your reaction may be that you've seen Newton's laws, you applied them in school.
你们的反应可能是,我已经见过牛顿定律了,以前在学校就学过
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