-a (b-a)(√a+√b) (b-a)(√a+√b)
----------- = ---------------------------- = --------------------- = -√a-√b
√a-√b (√a-√b)(√a+√b) a-
-a (b-a)(√a+√b) (b-a)(√a+√b)
----------- = ---------------------------- = --------------------- = -√a-√b
√a-√b (√a-√b)(√a+√b) a-