x It's the average value of a function, x in the region.

就是x乘以函数做积分的均值，区域中的。

youdao

We can use that to get information about maybe the region or about the average value of a function in that region and so on.

二重积分可以用来得到关于这个区域的某些信息，或者这个区域上的一个函数的平均值，等等。

youdao

As for a random signal, self-correlated function can always be the integrate token of its statistic average value.

对于一个随机信号，自相关函数往往最能完整地表征它的统计平均值。

youdao