for makky2

gistfile1.txt

library(ggplot2)

# make dataframe
x <- seq(0,3, by = 0.1)
y <- x^2 
xy <- data.frame(x = x, y = y)

# plot
p <- ggplot()
p <- p + geom_line(data = xy, aes(x = x, y = y))
p <- p + geom_hline(yintercept = c(0,2^2))
p <- p + geom_vline(xintercept = c(0,2))
p <- p + geom_ribbon(data = subset(xy, x <= 2), aes(x = x, ymin = y, ymax = 4), alpha = 0.2)
p