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# 									#
# plot.R <- an R script for plotting a function				#
# @ http://www.srcf.ucam.org/~lj237/plot.R				#
#									#
# Open this file from R by saving it somewhere and clicking "Open	#
# script" in the file menu. Anything in this file starting with # is a  #
# 'comment', i.e. something that doesn't do anything, just me talking	#
# to you. Anything without a # is an R command, which does something.	#
#									#
# By Luke, 16/10/07							#
#									#
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t <- seq(start=-0.5,end=10,len=500)
# "t <-" means "assign to t", and the seq() command puts 500 numbers 
# between -0.5 and 10 into t

Y <- t*exp(-t)
# this performs the operation ("times x by exp(-x)") on all the objects 
# in t, and stores all the answers in Y

plot(t,y,type="l",axes=FALSE,main=expression(Y==t*e^-t))
# the plot() command plots all the numbers in t and y against each
# other. 'type="l"' says that we want a line graph, and saying 
# "axes = FALSE" means that it won't put on any axis (we will add 
# these later). Finally, the "main =" part tells R what title we want, 
# and the expression() command says we want it as an equation

axis(side=1,pos=0)
axis(side=2,pos=0)
# finally, calling this command twice puts an axes at position 0 (i.e. t=0
# or y=0) on two sides (1 is the bottom one, 2 is along the side)