(1) _y_ = ½[ⁿ√](_a_ + √(_aa_ - 1)) +
½/[ⁿ√](_a_ + √(_aa_ - 1)), or
(2) _y_ = ½[ⁿ√](_a_ + √(_aa_ - 1)) +
½[ⁿ√](_a_ - √(_aa_ - 1)), or
(3) _y_ = ½/[ⁿ√](_a_ - √(_aa_ - 1)) +
½[ⁿ√](_a_ - √(_aa_ - 1)), or
(4) _y_ = ½/[ⁿ√](_a_ - √(_aa_ - 1)) +
½/[ⁿ√](_a_ + √(_aa_ - 1)).
Here it is to be noted, that if (_n_ - 1)/2 be an odd Number, the Sign
of the Root found must be contrary to it.