x <- seq(-pi, pi, 0.1)
plot(x, cos(x))

riqueza <- c(15,18,22,24,25,30,31,34,37,39,41,45)
area <- c(2,4.5,6,10,30,34,50,56,60,77.5,80,85)
area.cate <- rep(c("pequeno", "grande"), each=6)
 
plot(riqueza ~ area)
plot(area, riqueza) # o mesmo que o anterior
boxplot(riqueza ~ area.cate, col = "white")
barplot(riqueza)

par(mfrow=c(1,2))
plot(riqueza~area)
boxplot(riqueza~area.cate)