共50条信息
数列\(\{a_{n}\}\)满足\({{a}_{n+1}}=\dfrac{{{a}_{n}}}{2{{a}_{n}}+1}\),\({{a}_{3}}=\dfrac{1}{5}\)则\(a_{1}=\)________.
若数列\(\{ a_{n}\}\)满足\(a_{11}{=}\dfrac{1}{52}{,}\dfrac{1}{a_{n{+}1}}{-}\dfrac{1}{a_{n}}{=}5(n{∈}N^{{*}})\),则\(a_{1}{=}\) ______ .
设数列\(\{a_{n}\}\)的通项为\(a_{n}=2n-9(n∈N^{*})\),则\(|a_{1}|+|a_{2}|+…+|a_{15}|=\)________.
正项数列\(\{a_{n}\}\)满足:\(a_{1}=1\),\(a_{2}=2\),\(2a\rlap{_{n}}{^{2}}=a\rlap{^{2}}{_{n+1}}+a\rlap{^{2}}{_{n-1}}(n∈N^{*},n\geqslant 2)\),则\(a_{7}=\)________.
已知数列\(\{a_{n}\}\)满足\(a_{1}=1\),\(a_{2}=\dfrac{1}{2}\),且\(a_{n}(a_{n-1}+a_{n+1})=2a_{n+1}a_{n-1}(n\geqslant 2)\),则\(a_{2\;015}=\)____\(.\)
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