i am doing a work in rstudio, and i dont know how to use the function usr, anybody can tell me how to use it (the sintaxis, the arguments, etc)
I've never heard of the function usr, what package is it in?
To answer your question though, to find help with any function you can just run the command ?function in R and it will bring up it's documentation.
For example, ?usr should answer your question.
hey is a grafical function i guess (Because in tutorial they use it in this way: par(usr-c.......)
Okay, so usr is an argument of the par function (run the ?par command to find out more) which inputs a vector (x1, x2, y1, y2) and uses this vector to create the extremes of the plotting region. If I understand the documentation correctly (and I might not) if you used the vector (-10,10, -10, 10) it would give you the plot focused in on that region. Like this (not made in R because sometimes its easier to google for a picture):
