# Sinc function

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The sinc function, , is a useful function that is a little tricky to implement because it becomes as x approaches . Here is an implementation taken from the Boost library.

```
epsilon :: RealFloat a => a
epsilon = encodeFloat 1 (fromIntegral $ 1-floatDigits epsilon)
{- Boosted from Boost http://www.boost.org/boost/math/special_functions/sinc.hpp -}
sinc :: (RealFloat a) => a -> a
sinc x =
if abs x >= taylor_n_bound
then sin x / x
else 1 - x^2/6 + x^4/120
where
taylor_n_bound = sqrt $ sqrt epsilon
```