a <- 1 F1 <- function(t) 1 - 2*exp(-3*a*t) + exp(-6*a*t) F2 <- function(t) 1 - 4*exp(-3*a*t) + 2*exp(-4*a*t) + 2*exp(-5*a*t) - exp(-6*a*t) F3 <- function(t) 1 - 8*exp(-3*a*t) + 12*exp(-4*a*t) - 6*exp(-5*a*t) + exp(-6*a*t) t <- (0:2000)/1000 plot(t, sapply(t, F1), type="l", xlab="t", ylab="P(T<=t)") text(0.3, 0.6, labels="P(T1<=t)") points(t, sapply(t, F2), type="l") text(0.6, 0.55, labels="P(T2<=t)") points(t, sapply(t, F3), type="l") text(0.8, 0.5, labels="P(T3<=t)")