What symbol is used to identify change in position in physics formula?

Sorry, this is a literature site only. I would not be able to give you a very accurate answer.

The notation is used for displacement is ∆. Its the distance between the two points which is also called as change in position. Suppose a particles moves from r1 to r2 in a 2D coordinate axes . The change in position can be written as

∆r = r2-r1