[StefanOnRails]

Hi guys, I'm pretty new in Java and I have this problem: I was testing some Math functions when I tried to get sin of Math.PI using the following statement:

System.out.println( Math.sin(Math.PI) ); // output: 1.2246467991473532E-16

Don't get me wrong, I wasn't the best in my math class, but shouldn't this output 0 ?
I've tried to use this:

double pi = Math.toRadians(180);
System.out.println( Math.sin(pi) );

...but I got the same result

I've also tried to get cos of Math.PI and it worked fine. So what's the explanation?

[g00se]

Floating point values can only be approximated on computers (unless special classes like BigDecimal are used) so will rarely be exact. See http://mindprod.com/...atingpoint.html

[StefanOnRails]

Thanks for your reply, I have a better understanding over floating point numbers now (by the way, I managed to get my sin(PI) == 0 using Math.floor )

[g00se]

Good. Of course pi itself can never be represented exactly - even with BigDecimal