Also, it is cylindrically symmetric around the bonding axis, so this is how we know that it's a sigma orbital.

此外，它关于键轴是圆柱对称的，这就是为什么我们知道它是sigma轨道。

麻省理工公开课 - 化学原理课程节选

Well, the mean is always .2 no matter how many policies you write, so it's going to be--we're going to have a normal distribution centered on .2.

不论你签了多少份保单,均值永远是0.2,所以这就是一个关于x=0.2对称的,正态分布

耶鲁公开课 - 金融市场课程节选

That's a bell-shaped curve, but it's centered exactly on .2.

这是条钟形曲线,它关于x=0.2对称

耶鲁公开课 - 金融市场课程节选