How to produce a double-well graph in R

To create a double-well image as the one in the above, we can do it in three steps

(1) The left of the first bottom can use the graph of a parabolic function.

(2) From the first bottom to the second bottom can use the graph of a cosine function.

(3) The right of the second bottom can use the graph of another parabolic function.

The following R code generates the graph above:

x2<-c(0:100)*0.02+1

y2<-cos((x2-2)*pi)

x1<-c(0:100)*0.01

y1<-3*(x1-1)^2

x3<-c(0:100)*0.01+3

y3<-3*(x3-3)^2

jpeg("doublewell.jpg")

plot(x2,y2,xlim=c(0,4),ylim=c(0,3),'l',xlab="",ylab="",xaxt="n",yaxt="n")

lines(x1,y1)

lines(x3,y3)

dev.off()