save_figs = FALSE

# Plot the solution:
# 
ts = seq(0, 2*pi, length.out=200 )
ys = ts
mask = ts > pi
ys[mask] = -(pi/2)*cos(ts[mask]) - (1 + pi/2)*sin(ts[mask]) + (pi/2)*exp(pi-ts[mask])

# Plot the right-hand-side:
#
rhs = ts
rhs[mask] = pi*exp(pi-ts[mask])

if( save_figs ){ postscript("../../WriteUp/Graphics/Chapter3/chap_3_sect_5_prob_31_plot.eps", onefile=FALSE, horizontal=FALSE) }
plot(ts, ys, type='l', xlab='t', ylab='y(t)', main='Question 31')
lines(ts, rhs, type='l', col='red')
grid()
if( save_figs ){ dev.off() }