This is just some toy program I was trying. I fail to understand why this works:

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Prelude> zipWith (\ x y -> ((x ^ y) / (product [1..x]))) [1..3] [2,2,2]

[1.0,2.0,1.5]

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and this does not:

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Prelude> zipWith (\ x y -> ((y ^ x) / (product [1..x]))) [1..3] [2,2,2]

<interactive>:1:19:

Ambiguous type variable `a' in the constraints:

`Fractional a' arising from a use of `/' at <interactive>:1:19-44

`Integral a' arising from a use of `^' at <interactive>:1:20-24

Probable fix: add a type signature that fixes these type variable(s)

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Note that the "^" function has "x" and "y" flipped.

:t (^) says:

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(^) :: (Num a, Integral b) => a -> b -> a

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Could somebody please throw some light?

Thanks.