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

[Jianling Fan]

 Oops!

Thanks a lot! Jean

On 29 October 2015 at 15:45, Adams, Jean <jvadams at usgs.gov> wrote:
> 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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>
>



-- 
Jianling Fan
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