>>11714008>>11714026The trick is to use difference of squares in the linear term to get something that will be a difference of squares in the quadratic term, then quartic, and so on. This gives you a very easy closed form for some fixed k, so evaluating the limit comes down to evaluating a small rational expression. If you notice, the delta is a small nonnegative term less than 1, so by the Archimedean property, it approaches arbitrarily close to 0 as its exponent is taken to infinity. Hence the limit is the final expression on the bottom right.
