plot scale

plot(x, y, xaxt="n", yaxt="n", xlim=c(0, 4*pi), ylim=c(0, 10))
xat<-seq(0, 4*pi, by=pi)
yat<-seq(0, 10, by=2)
axis(side=1, at=xat, label=c("0", "pi", "2pi", "3pi", "4pi"))
axis(side=2, at=yat)