On Fri, Sep 9, 2016 at 12:24 PM, Hans W Borchers <[email protected]>
wrote:
> As the subject line says, we get different results for tan(pi/2) and
> tanpi(1/2), though this should not be the case:
>
> > tan(pi/2)
> [1] 1.633124e+16
>
> > tanpi(1/2)
> [1] NaN
> Warning message:
> In tanpi(1/2) : NaNs produced
>
> By redefining tanpi with sinpi and cospi, we can get closer:
>
> > tanpi <- function(x) sinpi(x) / cospi(x)
>
> > tanpi(c(0, 1/2, 1, 3/2, 2))
> [1] 0 Inf 0 -Inf 0
>
> Hans Werner
>
>
>
When I do a ?tanpi, I see the following:
‘tanpi(0.5)’ is ‘NaN’. Similarly for other inputs with fractional
part ‘0.5’.
I don't know why this is, but apparently the function is working as
documented. Whether that is correct or not is not for me to say.
--
Unix: Some say the learning curve is steep, but you only have to climb it
once. -- Karl Lehenbauer
Unicode: http://xkcd.com/1726/
Maranatha! <><
John McKown
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