Different results for tan(pi/2) and tanpi(1/2)
On Fri, Sep 9, 2016 at 12:24 PM, Hans W Borchers <hwborchers at gmail.com> 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.?
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