We can also use curve (as we would line or points) to draw points rather than a line: curve(x^2, type = 'p') Note: The plots are different because calling curve without xlim and ylim plots means that R doesn't know that we're going to add data outside the plotting region when we call points. We could also call these in the opposite order (replacing plot with points): curve((x), col = 'red', lwd = 2) So we could redraw our previous graph with gray points and a thick red curve: plot(y ~ x, col = 'gray', pch = 15)Ĭurve((x), add = TRUE, col = 'red', lwd = 2)

We could plot some data and then use curve to draw a y=x line on top of it: set.seed(1)Īnd, like all other plotting functions, curve accepts graphical parameters. We aren't restricted to using curve by itself either. For example, if we wanted to overlay the function y=x^2 on top of y=x we could type: curve((x)) We can also specify an add parameter to indicate whether to draw the curve on a new plotting device or add to a previous plot. Note: We have to type (x) rather than just x. For example, if we wanted to plot the line y=x, we would simply type: curve((x)) That expression should be a mathematical function in terms of x. The curve function takes, as its first argument, an R expression.

This tutorial shows some basic functionality. It is a neat little function that provides mathematical plotting, e.g., to plot functions. One of the many handy, and perhaps underappreciated, functions in R is curve.

Drawing two curves on one graph r