From: Joshua Wiley <jwiley.psych_at_gmail.com>

Date: Wed, 02 Jun 2010 09:15:40 -0700

Date: Wed, 02 Jun 2010 09:15:40 -0700

On Tue, Jun 1, 2010 at 9:59 PM, Shant Ch <sha1one_at_yahoo.com> wrote:

*> Hi
**>
*

> I was trying to have a graph whose axes are X axis: m, Y axis: var[X ((a,b) in suffix, and (n,d) in the power)].

*>
**> X ((a,b) in suffix, and (n,d) in the power)- X^(n,d) _ (a,b).
**>
**> Actually I require many plots involving different values of a,b,n,d, so need to keep this complicated notation.
**> The expression() didn't work out for this case. Can anyone help me out.
**> Thanks, in advance.
**> Shant
**>
**>
**>
**>
**>
**>
**> uniroot(function(x) x*(3^x)*log(4)-x*log(4/3)-(3^x)+1, lower = -2, upper = 2, tol = 0.001 )
**>
**> While using this I am getting the following error. Can anyone please help me out.
**> Error in uniroot(function(x) x * (3^x) * log(4) - x * log(4/3) - (3^x) + : f() values at end points not of opposite sign.
*

Here is your function:

temp.fun <- function(x) {

value <- x*(3^x)*log(4)-x*log(4/3)-(3^x)+1
return(value)

}

look what happens when you do:

temp.fun(-2)

temp.fun(2)

in both cases, it returns a positive value. uniroot() requires "The function values at the endpoints must be of opposite signs (or zero)", hence the error. I believe your function has a lower bound of 0, which is obtained when the input is 0. So one option would be to change your argument to uniroot() so that lower=0. Although the results are not particularly interesting in this case.

uniroot(function(x) x*(3^x)*log(4)-x*log(4/3)-(3^x)+1, lower = 0, upper = 2, tol = 0.001 )

**HTH,
**
Josh

*>
**> Thanks in advance.
**>
*

> Shant

*>
**>
**>
**> [[alternative HTML version deleted]]
**>
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**> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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**>
*

-- Joshua Wiley Senior in Psychology University of California, Riverside http://www.joshuawiley.com/ ______________________________________________ R-help_at_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.Received on Wed 02 Jun 2010 - 16:17:48 GMT

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