[R] Simple Problem: Plotting mathematical functions

[Matthieu Dubois]

Hi, 

you can use the curve() function for this. It is dedicated to plotting
functions. 

Here is an example

# turn your functions into r functions
f <- function(x) 0.25 * x^2 + 6.47 * x -32.6	
g <- function(x) 0.99*x^2 -6*x -195	
j <- function(x) 0.77*x^2 + 14*x -495		
k <- function(x) 0.001*x^2 + 65*x -785		
l <- function(x) 0.9*x^2 -2*x -636 

# plot f and g
curve(f, from=0, to=100, lty=1)
curve(g, add=TRUE, lty=2)


In this example, the parameters 'from' and 'to' define the domain over wich
all functions will be evaluated. The parameter add=TRUE is used to add 
the second function to the previous plot. 

HTH

Matthieu

Matthieu Dubois 
Post-doctoral fellow, 
Psychology Department, Univeristé Libre de Bruxelles