#postscript("../../WriteUp/Graphics/Chapter1/chap_1_sect_2_prob_11_plot.eps", onefile=FALSE, horizontal=FALSE)

ts = seq( 0, 20, length.out=200 )
y_1 = 49 * ( 1 - exp(-ts/5) ) 
y_2 = 49*tanh(ts/5)

plot( ts, y_1, type='l', col='blue', xlab='time', ylab='v(t)' )
lines( ts, y_2, type='l', col='red' )
grid()
legend('topleft', legend=c('exponential', 'tanh'), col=c('blue', 'red'), lty=c(1, 1))

#dev.off()