题型:解答题 题类:期末考试 难易度:难
已知数列\(\left\{ {{a}_{n}} \right\}\)的首项\({{a}_{1}}=1\),\({{S}_{n}}\)是数列\(\left\{ {{a}_{n}} \right\}\)的前\(n\)项和,且满足\(2\left( {{S}_{n}}+1 \right)=\left( n+3 \right){{a}_{n}}\).
\((1)\)求数列\(\left\{ {{a}_{n}} \right\}\)的通项公式;
\((2)\)设数列\(\left\{ {{b}_{n}} \right\}\)满足\({{b}_{n}}=\dfrac{1}{{{a}_{n}}{{a}_{n+1}}}\),记数列\(\left\{ {{b}_{n}} \right\}\)的前\(n\)项和为\({{T}_{n}}\),求证:\({{T}_{n}} < 3\).