在R中找到有理函数的局部最大值 [英] Finding the local maximum of a rational function in R

问题描述

我如何找到R中有理(多项式)函数的局部最大值，例如f(x)= 500 * t/(2 * t ^ 2 + 9)?我尝试了以下方法:

How would I find the local maximum of a rational (polynomial) function such as f(x) = 500*t/(2*t^2 + 9) in R? I tried the following:

t <- seq(0,10000,by=0.000001)
f <- 500*t/(2*t^2 + 9)
max(f)

但是我很快就用光了内存.

But I quickly ran out of memory.

推荐答案

所以，这就是我的操作方法.感谢G.和alistaire.

So, here is how I did it. Thanks to G. and alistaire.

f <- function(x){
  z <- 500*x/(2*x^2+9)
  return(z)
}

optimize(f,c(0,1000),maximum=TRUE)

Output:
$`maximum`
[1] 2.121332

$objective
[1] 58.92557

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