共50条信息
已知数列\(\left\{ {{a}_{n}} \right\}\)满足:\({{a}_{1}}=3\),\({{a}_{n+1}}=\dfrac{1}{1-{{a}_{n}}}\),则\({{a}_{2020}}=(\) \()\)
设\(f(n)=1+\dfrac{1}{2}+\dfrac{1}{3}+\cdots +\dfrac{1}{2n+1}(n\in {{N}^{*}})\),则\(n=1\)时,\(f(n)=\)( )
已知等差数列\(\{a_{n}\}\)中,\(a_{1}=-60\),\(a_{17}=-12\).
\((1)\)该数列第几项起为正?
\((2)\)前多少项和最小?求数列\(\{a_{n}\}\)的前\(n\)项和\(S_{n}\)的最小值
进入组卷