[R] Query on finding root

[Ben Bolker]

I would probably use the built in qdavies() function...

On Mon, Aug 28, 2023, 7:48 AM Leonard Mada via R-help <r-help using r-project.org>
wrote:

> Dear R-Users,
>
> Just out of curiosity:
> Which of the 2 methods is the better one?
>
> The results seem to differ slightly.
>
>
> fun = function(u){((26104.50*u^0.03399381)/((1-u)^0.1074444)) - 28353.7}
>
> uniroot(fun, c(0,1))
> # 0.6048184
>
> curve(fun(x), 0, 1)
> abline(v=0.3952365, col="red")
> abline(v=0.6048184, col="red")
> abline(h=0, col="blue")
>
>
>
> fun = function(u){ (0.03399381*log(u) - 0.1074444*log(1-u)) -
> log(28353.7/26104.50) }
> fun = function(u){ (0.03399381*log(u) - 0.1074444*log1p(-u)) -
> log(28353.7/26104.50) }
>
> uniroot(fun, c(0,1))
> # 0.6047968
>
> curve(fun(x), 0, 1)
> abline(v=0.3952365, col="red")
> abline(v=0.6047968, col="red")
> abline(h=0, col="blue")
>
> Sincerely,
>
> Leonard
>
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