[R] find max. value for a equation by optimize

[Adams, Jean]

If you read the help file for optimize, you will see that you need to set
the argument maximum to TRUE.

?optimize

optimize(sm, c(0, 50), maximum=TRUE)

Jean

On Thu, Oct 29, 2015 at 4:19 PM, Jianling Fan <fanjianling at gmail.com> wrote:

> Hello, everyone,
>
> I have a specific equation, When I draw it out, I found there is a
> max. value for it at about x=5. but I couldn't point it out by
> optimize(). Does anyone know why? Thanks!
>
> my code is:
>
> d50<-18.04
> c<-  -1.276
> dm<-147
>
> sm <- function (x) {
>
> 1/(1+(x/d50)^c)+(1-1/(1+(dm/d50)^c))*x/dm-(1/(1+((x-1)/d50)^c)+(1-1/(1+(dm/d50)^c))*(x-1)/dm)
> }
> curve(sm, 0,50)
> optimize(sm,c(0,50))
>
> The optimize() only give min. value but not max.
>
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