х√у -у√х
------------------- + у*(√х +√у)⁻¹ =
х-у
√х√у*(√х -√у) у
= --------------------------- + ------------------ =
(√х +√у)(√х -√у) √х +√у
√х√у у √у( √х +√у)
= -------------- + ------------------ = ----------------------------- =√у =у¹/²
(√х +√у) √х +√у √х +√у