I'm just starting to learn Haskell, and I'm having some confusion (I think) with how the type inference is working.  Can someone explain why, in ghc 6.8.2 this works:

*Main> (1/3)^3
3.7037037037037035e-2

But this doesn't

*Main> (\k -> (1/k) ^ k) 3

<interactive>:1:8:
    Ambiguous type variable `t' in the constraints:
      `Fractional t' arising from a use of `/' at <interactive>:1:8-10
      `Integral t' arising from a use of `^' at <interactive>:1:7-15
    Probable fix: add a type signature that fixes these type variable(s)

TIA,
Ben