I thought the same thing. I guess the confusion comes from thinking of the inverse of the function square root instead of the multiplicative inverse of the valu

I thought the same thing. I guess the confusion comes from thinking of the inverse of the function square root instead of the multiplicative inverse of the value of the square root function. Technically I suppose the terminology is a bit hand-wavy, since you could have also been referring to the additive inverse, but I think it's fairly common to talk about "inverses" of members of a field and assume that people know you mean multiplicative inverses. But that's exactly what isn't a safe assumption here, since you could be thinking about a function (which seems like the more natural interpretation), as opposed to a number.