#====================
# Figure 10.4.R.
# Plot of exponential growth function
# for three different growth rates.
#====================
m=5               # Initial size of exponentially changing quantity.
t=20*(0:100)/100  # Range of values of time from 0 to 20.
r=.04
n=m*exp(r*t)
plot(t,n,type="l",ylim=c(0,12))
r=-.04
n=m*exp(r*t)
points(t,n,type="l")
r=0
n=m*exp(r*t)
points(t,n,type="l",lty="dashed")