How to plot a function curve in R

I did some searching on the web, and this are some ways that I found:
The easiest way is using curve without predefined function
curve(x^2, from=1, to=50, , xlab=”x”, ylab=”y”)

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”)

If you want to use ggplot,
library(“ggplot2”)
eq = function(x){x*x}
ggplot(data.frame(x=c(1, 50)), aes(x=x)) +
stat_function(fun=eq)

You mean like this?
> eq = function(x){x*x}
> plot(eq(1:1000), type=’l’)

(Or whatever range of values is relevant to your function)