x <- seq(-5,5,length=10001)
plot(c(-5,5),c(-100,100),type="n", main = "ごく簡単な関数")
par(pch=".")
points(x,x, col = "black")
points(x,x^2, col="red")
points(x,x^3, col ="yellow")
points(x,-x,col = "green")
points(x, x^2-x , col = "blue")
points(x, x^5-x^4+x^3 , col = "grey")
dev.off()
