2.
在数列\(\left\{ {{a}_{n}} \right\}\)中,\({{a}_{1}}=1\),\({{a}_{n+1}}=2{{a}_{n}}+{{2}^{n}}\),设\({{b}_{n}}=\dfrac{{{a}_{n}}}{{{2}^{n-1}}}\).
\((1)\)证明:数列\(\left\{ {{b}_{n}} \right\}\)是等差数列;
\((2)\)求数列\(\left\{ {{a}_{n}} \right\}\)的通项公式;
\((3)\)求数列\(\left\{ {{a}_{n}} \right\}\)的前\(n\)项和.