#====================
# Figure 8.4.R.
# R script to draw the equation
# for the Golden Ratio.  (closeup version)
#====================
# xhi=2
xhi=1.61805
# xlo=-1
xlo=1.61800
x=xlo+(xhi-xlo)*(0:100)/100
y=x^2-x-1
plot(x,y,type="l",lwd=2)
y2=numeric(length(x))
points(x,y2,type="l",lty="dashed")

x1=((1+sqrt(1+4)))/2