How do we get rid of z? Well, if we are on the top surface, z So, I plug z equals z2 of x, y into the formula for R, whatever it may be.

怎样才能消去z？，考虑顶部曲面，通过函数z2给出。，z，is，given，by，this，formula，，z2，of，x，，y。,所以我把z=z2代入到R中，不管是什么。

youdao

So if we want to talk about the volume of that, we just talk about the surface area, which is 4 pi r squared, and we multiply that by the thickness d r.

如果我们要讨论它的体积，我们要用的是表面面积，也就是4πr的平方，乘以厚度dr

youdao

So if you have some region of space S and you call its boundary surface S and you let n be the normal vector that goes out of the region R.

如果存在一些区域空间,边界为曲面,定义n为指向区域R外的法向量。

youdao

So if we want to talk about the volume of that, we just talk about the surface area, which is 4 pi r squared, and we multiply that by the thickness d r.

如果我们要讨论它的体积，我们要用的是表面面积，也就是４πｒ的平方，乘以厚度ｄｒ

麻省理工公开课 - 化学原理课程节选

"Imagine that the mirror's surface is made of many smaller mirrors turned to different angles, like a disco ball, " said R.

CNN: Disco ball-inspired mirror gets rid of driver's blind spot