"Y.N." wrote in message:<c8cs4p$l1k$1@nr1.vectant.ne.jp>
>
>?? (x_1?x)'?x ???x_1 ? x ?????????
>?? (x_1?x)'?x_1 ?? ?x_1 ? x ????????????
>
>?? (x_1?x)' ??x_1 ? x ???????????????????


(x_1?x)'?x_1 ?????x_1?x ???????????????
x_1?x ?????????(x_1?x)'?x_1?x ?????

???lim{x_1?x}(x_1)?x ?????