A = matrix(c(1, 1, 2, -2), nrow=2, ncol=2, byrow=T) solve(A, c(2, 3)) ts = seq(0, 2, length.out=100) x1 = (7/4) * (+1) * exp(ts) + (1/4) * (+1) * exp(2*ts) x2 = (7/4) * (+2) * exp(ts) + (1/4) * (-2) * exp(2*ts) #postscript("../../WriteUp/Graphics/Chapter7/chap_7_sect_5_prob_27_plot.eps", onefile=FALSE, horizontal=FALSE) par(mfrow=c(1, 2)) plot(x1, x2, type='l') points(c(2), c(3), type='p', cex=1.5, pch=19) grid() x_min = min( c(x1, x2) ) x_max = max( c(x1, x2) ) plot(ts, x1, type='l', col='green', ylim=c(x_min, x_max), xlab='time', ylab='x') points(ts, x2, type='l', col='red') points(c(0, 0), c(2, 3), type='p', cex=1.5, pch=19, col=c('green', 'red')) legend('topright', c('x1', 'x2'), col=c('green', 'red'), lty=c(1, 1)) grid() par(mfrow=c(1, 1)) #dev.off()