If I told you 3x + 2y = 9 and 4x + 6y = 6, you certainly know how to solve for x and y, right?
如果我给出 3x + 2y = 9,和 4x + 6y = 6 这两个方程,你们肯定知道怎么解出 x 和 y,对吧
Well you know what a point is, it's got an x- and a y- coordinate, it's natural to think about those two things as belonging as a single entity.
把这两个坐标认为,是属于一个独立的实体,是理所当然的事情,因此实现这个目的的。
Say, Binky, I don't think dereferencing y is a good idea because, you know, setting up the pointee is a separate step and I don't think we ever did it.
你说,Binky,我不认为不关联y是一个好主意,因为,你懂的,调定指针数据是一个单独的步骤,我不认为我们这样做了。
If you know the second derivative of y to be a, then the answer looks like this.
如果你知道y的二阶导数是a,那么这就是答案
So we're talking about an experiment when you generate-- Each experiment generates both an x and a y observation and we know when x is high, y also tends to be high, or whether it's the other way around.
这里说的是由试验产生的,每一次试验可以获得一组x与y的观察值,当x值大的时候,y值可能也大,或者相反
They might very well be storing the addresses of memory elsewhere, but we just needed them as sort of a cheat sheet, a little address card to know where the original values x and y were.
它们存储在内存的其他地方是可以的,但是我们需要一个备忘单,一个地址卡,来知道,原始的值x和y是什么。
So, that is a tricky problem to begin with because if you take this formula here, it tells you y if you know t, but no, we're not saying that.
以这个问题刚开始的时候有点难度,因为如果你要用这个公式,求y的时候就一定要知道t,但是,我们不知道
By the way, I didn't tell you this but I think you know that I picked my origin to be here and measured y positively to be upwards and I called that 15 meters.
顺便说一下,虽然我没明确指出,但我想你们应该都知道,我把原点取在这里,并规定y的正方向朝上,我设把这里的高度为15米
If you are describing a particle with location R, the vector we use typically to locate a particle, R then R is just i times x + j times y, because you all know that's x and that's y.
如果你要描述一个位移为 R 的质点,这个矢量一般用表示质点 R 的位移,R 可表示为 i ? x + j ? y,显然你们都知道这段是 x,那段是 y
So, what we have found out so far, I'm purposely going from x to y because I want you to know that the unknown variable can be called an x or can be called a y.
到目前为止,我们有这些结论,我特地把x换成y,因为我想让你们明白,未知变量既可以写成x,也可以写成y
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