How to create two line charts in the same plot in R?

We can do this by using lines function after plotting the first chart.

Example

> x <- seq(-3, 3, 0.025) > X1 <- pnorm(x) > X2 <- pnorm(x, 2, 1) > plot(x, X1, type="l",col="red", ylab="X") > lines(x, X2, col="green")