--- Square root v8: using Haskell's iterate control abstraction

sqrt8 x = head (dropWhile (not . goodEnough) sqrtGuesses)
   where
      goodEnough guess = abs (x - guess*guess)/x < 0.00001
      improve guess = (guess + x/guess)/2.0
      sqrtGuesses = iterate improve 1


{-- To test it:

sqrt8 10

--}

sqrt8guesses x = iterate improve 1
   where
      improve guess = (guess + x/guess)/2.0

{-- To test it:

take 5  (sqrt8guesses 10)

--}