1 1
------- + -----
(x+y) (x-y) x
--------------------- = - ----
1 1 y
------- - -----
(x+y) (x-y)
1) 1 1 (x-y+x+y) 2x
------- + ----- = -----------------= -------------
(x+y) (x-y) (x-y)(x+y) (x-y)(x+y)
1 1 (x-y)-(x+y) -2y 2x -2y -x
2) ------- - ----- = -------------- = ------------- 3) ------------ :------------- = ----
(x+y) (x-y) (x-y)(x+y) (x-y)(x+y) (x-y)(x+y) (x-y)(x+y) y
ч.т.д.