[R] How to change min and max of plot axis

[Luis Orlindo Tedeschi]

All; this might be an easy question but I cannot make it work. I would
like to set the min and max of the y axis of a plot. I know I have to
use par("usr"), but after I do the plot() the axis values get changed.

x<-rnorm(20)
Y<-x+rnorm(20,0,.1)
plot(y,x)
par("usr")

# let's say I have -2.8 1.15 -2.8 1.16 for par("usr")
# let's say I need to change the Y-axis to be -5 to 5

usr<-par("usr")
par(usr=c(usr[1:2],-5,5))
plot(y,x)

# it does not take the -5 to 5???

Is there any way to set the axis values?

Thanks