26
次の数列の和\(S\)を求めよ。
(1) \(\dfrac{1}{1\cdot2\cdot3}\),  \(\dfrac{1}{2\cdot3\cdot4}\),  \(\dfrac{1}{3\cdot4\cdot5}\),  …,  \(\dfrac{1}{n(n+1)(n+2)}\)
(2) \(\dfrac{1}{1+\sqrt{3}}\),  \(\dfrac{1}{\sqrt{2}+\sqrt{4}}\),  \(\dfrac{1}{\sqrt{3}+\sqrt{5}}\),  …,  \(\dfrac{1}{\sqrt{n}+\sqrt{n+2}}\)　(\(n\geqq 2\))