R So let's get rid of R in this expression here.

利用这个式子，我们就可以消去。

麻省理工公开课 - 热力学与动力学课程节选

We know it's going around in a circle because if I find the length of this vector, which is the x-square part, plus the y-square part, I just get r square at all times, because sine square plus cosine square is one.

我们之所以知道它做圆周运动,是因为我求出了这个矢量的模长,也就是 x 的平方加上 y 的平方,我就得到了它在任意时刻的模长平方,因为正弦平方加余弦平方始终等于1

耶鲁公开课 - 基础物理课程节选

If you get them backwards, logr you will integrate one over r and will get log r.

如果你逆推的话，对1/r积分得到。

麻省理工公开课 - 固态化学导论课程节选

So we have the operationon the wave function in terms of r, theta, and phi and remember this e is just our binding energy for the electron, and we get back out this wave function.

我们用r，θ，φ来表示,将算符作用于波函数,而且记住e仅仅是电子结合能，然后后面加上波函数。

麻省理工公开课 - 化学原理课程节选

When you get one over R, you get a gradual fall.

当你用1除以R，你得到逐渐的下降。

麻省理工公开课 - 固态化学导论课程节选

If you get one over R squared, it'll be a little steeper.

如果你用1除以R的平方，它会变得稍微陡峭一些。

麻省理工公开课 - 固态化学导论课程节选

So, we can get from these energy differences to frequency h by frequency is equal to r sub h over Planck's constant 1 times 1 over n final squared minus 1 over n initial squared.

所以我们通过不同能量,得到不同频率，频率等于R下标,除以普朗克常数乘以1除以n末的平方减去。

麻省理工公开课 - 化学原理课程节选

So, the number of nuclei, 119 if we were to sit and count these as well, is 119. So, we'll multiply that by just pi, r squared, to get that cross-section, and divide all of that by 1 . 39 meters squared.

如果你们数的话，原子核的数是，我们用它乘以πr的平方，得到横截面积，除以1。39平方米。

麻省理工公开课 - 化学原理课程节选