[R] calculating error

[Deepayan Sarkar]

On Sunday 12 September 2004 13:28, Branimir K. Hackenberger wrote:
> Could anybody explain this results?
>
> >sin(2*pi)
>
> -2.449213e-16         #should be zero

It is, in the sense that 

> all.equal(sin(2*pi), 0)
[1] TRUE


> >(10^16)*sin(log2(4)*pi)
>
> -2.449213             #should be zero too
>
>
> and explain what to do to correct this events?

For starters, you need to invent and then use an infinite precision 
computer where the variable 'pi' is really the ratio between the 
circumference and radius of a circle, and not just a finite precision 
approximation of it. Good luck trying :-)

Deepayan