How to plot a function curve in R

What are the alternatives for drawing a simple curve for a function like

eq = function(x){x*x}

in R?

4 Answers

plot has a plot.function method

plot(eq, 1, 1000)

Or

curve(eq, 1, 1000)

The easiest way is using curve without predefined function

curve(x^2, from=1, to=50, , xlab="x", ylab="y")

enter image description here

You can also use curve when you have a predfined function

eq = function(x){x*x}
curve(eq, from=1, to=50, xlab="x", ylab="y")

enter image description here

If you want to use ggplot, you have a choise between qplot 

library("ggplot2")
eq = function(x){x*x}
qplot(c(1,50), fun=eq, stat="function", geom="line", xlab="x", ylab="y")

enter image description here

and ggplot

library("ggplot2")
eq = function(x){x*x}
ggplot(data.frame(x=c(1, 50)), aes(x=x)) + stat_function(fun=eq, geom="line") + xlab("x") + ylab("y")

enter image description here