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            • 1.

              若各项均为正数的数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\),且\(2 \sqrt[]{S_{n}}=a_{n}+1 (n∈N*)\).

              \((1)\)求数列\(\{a_{n}\}\)的通项公式;

              \((2)\)若正项等比数列\(\{b_{n}\}\),满足\(b_{2}=2\),\(2b_{7}+b_{8}=b_{9}\),求\(T_{n}=a_{1}b_{1}+a_{2}b_{2}+…+a_{n}b_{n}\);

              \((3)\)对于\((2)\)中的\(T_{n}\),若对任意的\(n∈N^{*}\),不等式\(λ·(-1)^{n} < \dfrac{1}{2^{n+1}}(T_{n}+21)\)恒成立,求实数\(λ\)的取值范围.

            • 2.

              \(《\)九章算术\(》\)中的“竹九节”问题:现有一根\(9\)节的竹子,自上而下各节的容积成等差数列,上面\(4\)节的容积共\(3L\),下面\(3\)节的容积共\(4L\),则第\(5\)节的容积为              L.

            • 3.

              \(7\)月份,有一款新服装投入某市场销售,\(7\)月\(1\)日该款服装仅销售出\(3\)件,\(7\)月\(2\)日售出\(6\)件,\(7\)月\(3\)日售出\(9\)件,\(7\)月\(4\)日售出\(12\)件,以后每天售出的件数分别递增\(3\)件直到日销售量达到最大\((\)只有\(l\)天\()\)后,每天销售的件数开始下降,分别递减\(2\)件,到\(7\)月\(31\)日刚好售出\(3\)件.

                  \((1)\)问\(7\)月几号该款服装销售件数最多\(?\)其最大值是多少\(?\)

                  \((2)\)按规律,当该商场销售此服装达到\(200\)件时,社会上就开始流行,而日销售量连续下降并低于\(20\)件时,则不再流行,问该款服装在社会上流行几天\(?\)说明理由.

            • 4.

              等差数列\(\left\{ {{a}_{n}} \right\}\)的公差为\(d\),关于\(x\)的不等式\({{a}_{1}}{{x}^{2}}+\left( \dfrac{d}{2}-{{a}_{1}} \right)x+c\geqslant 0\)的解集为\(\left[ \dfrac{1}{3},\dfrac{4}{5} \right]\),则使数列\(\left\{ {{a}_{n}} \right\}\)的前\(n\)项和\({{S}_{n}}\)最小的正整数\(n\)的值为                  

            • 5.

              已知数列\({a_{n}}\)的通项公式为\({a}_{n}= \dfrac{1}{1+2+3+…+n} \),

              \((1)\)求\({a}_{1},{a}_{2},{a}_{3} \);    

              \((2)\)求这个数列的前\(n\)项和\(;\)

            • 6.

              设数列\(\left\{ {{a}_{n}} \right\}\)满足\({{a}_{1}}+2{{a}_{2}}=2\),且对任意的\(n\in {{N}^{*}}\),点\({{P}_{n}}(n,{{a}_{n}})\)都有\(\overrightarrow{{{P}_{n}}{{P}_{n+1}}}=(1,2)\),则数列\(\left\{ {{a}_{n}} \right\}\)的前\(n\)项和为__________.

            • 7.

              设\({{S}_{n}}\)是等差数列\(\left\{ a{}_{n} \right\}\)的前\(n\)项和,若\( \dfrac{{a}_{5}}{{a}_{3}}= \dfrac{5}{9}, \)则\( \dfrac{{S}_{9}}{{S}_{5}} =(\)   \()\)

              A.\(1\)
              B.\(-1\)
              C.\(2\)
              D.\(\dfrac{1}{2}\)
            • 8.

              已知在等比数列\(\{{{a}_{n}}\}\)中,\({{a}_{1}}=1\),且\({{a}_{2}}\)是\({{a}_{1}}\)和\({{a}_{3}}-1\)的等差中项.

              \((1)\)求数列\(\{{{a}_{n}}\}\)的通项公式;

              \((2)\)若数列\(\{{{b}_{n}}\}\)满足\({{b}_{n}}=2n+{{a}_{n}}(n\in {{N}^{*}})\),求\(\{{{b}_{n}}\}\)的前\(n\)项和\({{S}_{n}}\).

            • 9.

              已知等差数列\(\{a_{n}\}\)的前\(n\)项和为\(Sn\),等比数列\(\{b_{n}\}\)的前\(n\)项和为\(Tn\),\(a_{1}=-1\),\(b1=1\),\(a3+b2=2\).

              \((1)\)若\(a3+b2=5\),求\(\{b_{n}\}\)的通项公式;

              \((2)\) 若\(T=21\),求\(S_{1}\)

            • 10.

              填空题

              \((1)\triangle ABC\)中,\(A={{60}^{\circ }}\),\(b = 1\),\({S}_{∆ABC}= \sqrt{3} \),则\( \dfrac{a+b+c}{\sin A+\sin B+\sin C}= \)________ .

              \((2)\)在公差不为\(0\)的等差数列\(\left\{{{a}_{n}}\right\} \)中,\({a}_{1}+{a}_{3}=8 \),且\(a_{4}\)为\(a_{2}\)和\(a_{9}\)的等比中项,则\(a_{5}=\)_____.

              \((3)∆ABC \)三内角\(A\),\(B\),\(C\)的对边分别为\(a\),\(b\),\(c\),\( \sqrt{3}\sin A-a\cos B-2a=0 \),则\(∠B= \)_______.

              \((4)\)已知数列\(\left\{{{a}_{n}}\right\} \)中,\({{a}_{1}}=-60,{a}_{n+1}={a}_{n}+3 \),则\(\left|{a}_{1}\right|+\left|{a}_{2}\right|+\left|{a}_{3}\right|+……+\left|{a}_{30}\right|= \)___________.

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