On Mon, Dec 22, 2008 at 7:27 PM, Daniel Finnie <dan / danfinnie.com> wrote:
> Hi, I was wondering about this expression and its siblings:
>
>> Math.sin(rand(2 * Math::PI))
>
> The documentation
> <http://www.ruby-doc.org/core/classes/Kernel.html#M005977>states that
> rand(num) will pick a random integer between 0 and num.abs.to_i
> (unless this is different in JRuby).  Therefore, the only values that can
> come out of this expression are sin(0), sin(1), ... sin(6) which are 0,
> .841, .909, .141, -.757, -.960, and -.279 (of course these are different for
> cosine).  Is it just the range -1<y<1?  Would rand(2)-1 suffice?  What is
> the significance of these numbers and doing rand(2pi) instead of rand(6)?

No significance other than trying to finish before  1:00.  :-)  Maybe
I was thinking: sin(rand * 2 * PI?  But, yeah rand * 2 - 1 would have
sufficed there.

Thanks.