职教组卷基于海量职教高考试题库建立的在线组卷及学习系统
职教组卷
科目:

选择章节

总题量:517 选择本页全部试题
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知公差不为零的等差数列\(\{a_{n}\}\)和等比数列\(\{b_{n}\}\)都是首项为\(1\)的数列,且\(a_{2}=b_{2}\),\(b_{4}=a_{2}a_{5}.\)
    \((1)\)求数列\(\{b_{n}\}\)的通项公式;
    \((2)\)令\(c_{n}=b_{a_{n}}\),求数列\(\{c_{n}\}\)的前\(n\)项和\(T_{n}.\)
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),且\(a_{2}=20\),\(S_{n}=4n^{2}+kn.\)
    \((1)\)求数列\(\{a_{n}\}\)的通项公式;
    \((2)\)若数列\(\{b_{n}\}\)满足\(b_{1}=3\),\(b_{n}-b_{n-1}=a_{n-1}(n\geqslant 2)\),求数列\(\{\dfrac{1}{b_{n}}\}\)的前\(n\)项和\(T_{n}.\)
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知数列\(\{a_{n}\}\)满足\((a_{n+1}-2)(a_{n}-2)=2(a_{n}-a_{n+1})\),\(a_{1}=3\),令\(b_{n}=\dfrac{1}{a_{n}-2}.\)
    \((1)\)求证:数列\(\{b_{n}\}\)是等差数列;
    \((2)\)求数列\(\{\dfrac{1}{b_{n}\cdot b_{n+1}}\}\)的前\(n\)项和\(S_{n}.\)
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知数列\(\{a_{n}\}\)满足\(a_{1}=\dfrac{1}{2}\),\(a_{n+1}-a_{n}+2a_{n+1}a_{n}=0(n\in N*).\)
    \((1)\)证明:数列\(\{\dfrac{1}{a_{n}}\}\)是等差数列,并求数列\(\{a_{n}\}\)的通项公式;
    \((2)\)设\(S_{n}\)为数列\(\{a_{n}a_{n+1}\}\)的前\(n\)项和,证明\(S_{n}< \dfrac {1}{4}.\)
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    在等差数列\(\{a_{n}\}\)中,\(a_{4}=7\),\(3a_{3}+a_{5}=24\),数列\(\{b_{n}\}\)满足\(b_{1}b_{2}b_{3}\)……\(b_{n}=2^{\frac{n(n+1)}{2}}.\)
    \((1)\)求数列\(\{a_{n}\}\)和\(\{b_{n}\}\)的通项公式;
    \((2)\)若____,求数列\(\{c_{n}\}\)的前\(n\)项和\(S_{n}.\)
    在①\(c_{n}=a_{n}b_{n}\),②\(c_{n}=\dfrac{2}{a_{n}a_{n+1}}+b_{n}\),③\(c_{n}=\dfrac{a_{n}+4}{a_{n}a_{n+1}b_{n+1}}\)这三个条件中任选一个补充在第\((2)\)问中,并作答.
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知等差数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),\(a_{4}=4\),\(S_{8}=12.\)
    \((1)\)求\(S_{n}\);
    \((2)\)求数列\(\{\dfrac{1}{a_{n}a_{n+1}}\}\)的前\(n\)项和.
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),且\(a_{1}=1\),\(S_{n+1}-1=2S_{n}+n.\)
    \((1)\)求数列\(\{a_{n}\}\)的通项公式;
    \((2)\)求数列\(\{\dfrac{2^{n}}{a_{n}a_{n+1}}\}\)的前\(n\)项和\(T_{n}.\)
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    在①\(3S_{n+1}=S_{n}+1\),\(a_{2}=\dfrac{1}{9}\);②\(S_{n}+a_{n}=1\);③\(a_{1}=1\),\(a_{n+1}=2S_{n}+1\)这三个条件中任选一个,补充在下面问题中,并完成解答.
    已知数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),且满足____.
    \((1)\)求\(\{a_{n}\}\)的通项公式;
    \((2)\)求\(a_{1}a_{3}+a_{3}a_{5}+a_{5}a_{7}+\)…\(+a_{2n-1}a_{2n+1}\)的值.
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知等差数列\(\{a_{n}\}\)中,公差\(d>0\),其前\(n\)项和为\(S_{n}\),\(a_{1}+a_{4}=14\),且\(a_{1}\),\(a_{2}\),\(a_{7}\)成等比数列.
    \((1)\)求数列\(\{a_{n}\}\)的通项公式及前\(n\)项和\(S_{n}\);
    \((2)\)令\(b_{n}=\dfrac{2S_{n}}{2n-1}\),\(f(n)=\dfrac{b_{n}}{(n+16)b_{n+1}}(n\in N*)\),求\(f(n)\)的最大值.
  • 题型:解答题 题类:模拟题 难易度:较易

    年份:2021

    已知公差不为零的等差数列\(\{a_{n}\}\)满足\(a_{3}=6\),且\(a_{1}\),\(a_{2}\),\(a_{4}\)成等比数列.
    \((1)\)求\(\{a_{n}\}\)的通项公式\(a_{n}\);
    \((2)\)设\(S_{n}\)为数列\(\{a_{n}\}\)的前\(n\)项和,求数列\(\{\dfrac{1}{S_{n}}\}\)的前\(20\)项和.