postscript("../ps/19-coseno.ps",
  width=2.0,height=0.6,
  horizontal=FALSE,onefile=FALSE,
  paper="special");
intx=c(-2*pi,2*pi); inty=c(-1,1)
par(mai=c(0,0,0,0))
par(lwd=0.5, bg="yellow")
plot(intx,inty,type="n",xlab="",ylab="",
  asp=1,axes=FALSE,frame.plot=TRUE)
x=seq(-2*pi,2*pi,length=1000)
lines(x,cos(x))
lines(c(-2*pi,2*pi),c(1,1))
lines(c(-2*pi,2*pi),c(-1,-1))
dev.off()