On Jan 22, 2010, at 6:49 PM, Marlin Keith Cox wrote:
I can plot this just fine:
t<-seq(0,4, by=.1)
y<- t^3-6*t^2+5*t+30
plot(t,y ,xlab="t-values", ylab="f(t)", type="l")
This is the first derivative, how I I make a similar plot?
t<-seq(0,4, by=.1)
y<- t^3-6*t^2+5*t+30
y1<-D(expression(t^3-6*t^2+5*t+30), 't')
There might be some sort of deparse() operation that one could do on
y1, but what follows sidesteps that level of programming.
y1fn <- function(t) {3 * t^2 - 6 * (2 * t) + 5}
par(new=TRUE)
plot(t, y1fn(t), ylab="", xlab="", axes=FALSE)
axis(side=4, at=seq(-7,5,by=1) )
--
David.
Thanks ahead of time.
kc
On Fri, Jan 22, 2010 at 12:41 PM, Doran, Harold <hdo...@air.org>
wrote:
D(expression(t^3-6*t^2+5*t + 30), 't')
3 * t^2 - 6 * (2 * t) + 5
D(D(expression(t^3-6*t^2+5*t + 30), 't'), 't')
3 * (2 * t) - 6 * 2
-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org
]
On Behalf Of Marlin Keith Cox
Sent: Friday, January 22, 2010 4:37 PM
To: r-help@r-project.org
Subject: [R] first and second derivative calculation
I would like to calculate a first and second derivative and am having
problems finding a simple solution. My syntax may be off as I am
not a
mathematician, so pardon ahead of time.
data:
t<-seq(0,4, by=.1)
The function is:
H(t) = t^3-6*t^2+5*t + 30
from here I plot the curve:
plot(x,y ,xlab="x-values", ylab="f(x)", type="l")
But would like to similarly plot the curve for both the first and
second
derivatives.
I can calculate the derivatives by hand but would like to get R to
do this
for me.
by hand:
H'(t) = 3*t^2 - 12*t + 5
H''(t) = 6*t-12
Keith
--
M. Keith Cox, Ph.D.
Alaska NOAA Fisheries, National Marine Fisheries Service
Auke Bay Laboratories
17109 Pt. Lena Loop Rd.
Juneau, AK 99801
keith....@noaa.gov
marlink...@gmail.com
U.S. (907) 789-6603
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html
>
and provide commented, minimal, self-contained, reproducible code.
--
M. Keith Cox, Ph.D.
Alaska NOAA Fisheries, National Marine Fisheries Service
Auke Bay Laboratories
17109 Pt. Lena Loop Rd.
Juneau, AK 99801
keith....@noaa.gov
marlink...@gmail.com
U.S. (907) 789-6603
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
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.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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.
