For example if the variable x stands for the movement of an object then Dx means the change in movement Scientists use this mathematical meaning of delta often in physics chemistry and engineering and it appears often in word problems. Unknown value to find. Information and translations of distance in the most comprehensive dictionary definitions resource on the web.
Not all mathematical functions have periods.
The definition and the value of the symbols are constant. In mathematics a distance function or metric is a generalization of the concept of physical distance. In basic mathematics there are many ways of saying the same thing. So pi means 314 in math terms.