Math.sin: sin(pi/6) = 0.4999999999999999994

[Ashi_Mashi2]

Hey guys,

I have a problem and I found it in many Java calculator applications: why does sin(pi/6)=0.49999...9994 instead of just 0.5? I know it is because of rounding errors, but, does anyone have any solutions to this? (I tried increasing the accuracy of Math.PI, still doesnt work:S)

Thanks in advance

[Hikaru79]

I think this can be chalked up to the way that floating point decimals are represented by the computer. This problem is not unique to java. For example, here it is in Python:

code:

hikaru79@navi:~$ python Python 2.4.2 (#2, Sep 30 2005, 21:19:01) [GCC 4.0.2 20050808 (prerelease) (Ubuntu 4.0.1-4ubuntu8)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> from math import pi, sin >>> sin(pi/6) 0.49999999999999994 >>>

So it's not just you I don't think there is much you can do about it, except deal with it manually.

[Andy]

yea hikaru is right, the reason is because pi is not exactly pi, but rather some decimal representation, thats why trignometric functions are off