[Haskell-cafe] Debugging Newton's method for square roots

I am new to Haskell and need help in debugging my code. I wrote the following function for calculating square roots using Newton's method: my_sqrt :: Float -> Float my_sqrt x = improve 1 x where improve y x = if abs (y * y - x) < epsilon then y else improve ((y + (x/y))/ 2) x epsilon = 0.00001 This works for several examples that I tried out but goes into an infinite loop for my_sqrt 96. How do I go about debugging this code in GHC or Hugs? (The equivalent code is well-behaved on MIT Scheme)