I'm trying to do a project that uses the trigonometric functions, but I'm having some trouble with them.

When I type in this code:

```
import math
print 0.5+math.cos((2*math.pi)/3)
```

I get the answer 2.22044604925e-016. That's obviously not right. cos((2*pi)/3) is -0.5, so I should get the answer 0. Can anybody help me?