simple trig help

[pepsicoder]

The following code is driving me mad why is my trace cos value not zero but -1.836909530733566e-16 please im going out of my head checked it on 2 calculators gives 0 which is correct please help cheers.

var a:Number=(270*Math.PI)/180;

var xx:Number=Math.cos(a);
var yy:Number=Math.sin(a);

trace("cos x = "+xx); // why is this value not zero
trace("sin y = "+yy); // this is correct displaying -1

[yasunobu13]

It's just a rounding error. The number that it is outputting is very close to zero. This has to do with the way floating point calculations are done in the computer. They can't be exactly correct.

[Kid Charlie]

This seems to be a bug. On the positive side, however, the number it returns is pretty darn close to 0. That's what piqued my interest in this because a lot of my programs rely on cos. This should be reported.

[pepsicoder]

Cheers my friends for the confirmation.