[R] Graphing the Area of Definite Integral

[peter dalgaard]

Something like this?

f <- function(x) x^3-2*x
curve(f(x), from=0, to=4)
abline(h=0)
n <- 16
dx <- 4/n
right <- (1:n)*dx
left <- right - dx
mid <- right - dx/2
fm <- f(mid)
points(mid, fm)
rect(left,0,right,fm)

sum(fm*dx)

1/4 * 4^4 - 4^2


-pd


On 27 Nov 2015, at 13:52 , Steven Stoline <sstoline at gmail.com> wrote:

> Dear All:
> 
> I am trying to explain to my students how to calculate the definite
> integral using the Riemann sum. Can someone help me to graph the area under
> the curve of the function, showing the curve as well as the rectangles
> between 0 and 4..
> 
> *f(x) = x^3 - 2*x *
> 
> over the interval [0 , 4]
> 
> 
> 
> with many thanks
> steve
> 
> -- 
> Steven M. Stoline
> 1123 Forest Avenue
> Portland, ME 04112
> sstoline at gmail.com
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com