#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
#
#-----

save_plots = F

# Chapter 5: Exercise 77
#
x = seq( from=0, to=30, length.out=100 )
y = 30 - x 

if( save_plots ){ postscript("../../WriteUp/Graphics/Chapter5/ex_77.eps", onefile=FALSE, horizontal=FALSE) }

plot( x, y, type='l', xlim=c(0,+40), ylim=c(0,30) ) 

y = 20 - x 
lines( x, y, type='l', col='black' )

abline( h=0 )
abline( v=0 ) 

polygon( c(20,30,0,0), c(0,0,30,20), col='gray' )

grid()

if( save_plots ){ dev.off() }