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            • 1.

              已知从\(1\)开始的连续奇数蛇形排列形成宝塔形数表,第一行为\(1\),第二行为\(3\),\(5\),第三行为\(7\),\(9\),\(11\),第四行为\(13\),\(15\),\(17\),\(19\),\(…\),如图所示,在宝塔形数表中位于第\(i\)行、第\(j\)列的数记为\(a_{i,j}\),比如\(a_{3,2}=9\),\(a_{4,2}=15\),\(a_{5,4}=23.\)若\(a_{i,j}=2113\),则\(i+j=\)________.

            • 2.

              \((1)\)已知\(\sin α= \dfrac{3}{5}\),\(α∈( \dfrac{π}{2},π)\),则\(\cos \alpha =\)________,\( \dfrac{\cos 2α}{ \sqrt{2}\sin (α+ \dfrac{π}{4})}=\)________.

              \((2)\)已知数列\(\{a_{n}\}\)的首项为\(1\),数列\(\{b_{n}\}\)为等比数列且\(b_{n}= \dfrac{a_{n+1}}{a_{n}}\),若\(b_{10}·b=2\),则\({{b}_{7}}{{b}_{14}}=\)_____,\(a_{21}=\)________.

              \((3)\)计算:\(\tan 20^{\circ}+\tan 40^{\circ}+ \sqrt{3}\tan 20^{\circ}\tan 40^{\circ}=\)________,\( \dfrac{ \sqrt{3}\tan 12^{\circ}-3}{(4\cos ^{2}12^{\circ}-2)\sin 12^{\circ}}=\)________.

              \((4)\)数列\(\left\{ {{a}_{n}} \right\}\)满足\({{a}_{1}}=1\),\(\sqrt{\dfrac{1}{{{a}_{n}}^{2}}+2}=\dfrac{1}{{{a}_{n+1}}}\left( n\in {{N}^{*}} \right)\),记\({{b}_{n}}={{a}_{n}}^{2}\),则数列\(\left\{ {{a}_{n}} \right\}\)的通项公式\({{a}_{n}}=\)____________,数列\(\left\{ {{b}_{n}}{{b}_{n+1}} \right\}\)前\(n\)项和\({{S}_{n}}=\)___________.

              \((5)\)在\(200 m\)高的山顶上,测得山下一塔顶与塔底的俯角分别为\(30^{\circ}\)与\(60^{\circ}\),则塔高是_____\(m\).

              \((6)\)若\(\sin \alpha +\sin \beta =\dfrac{\sqrt{2}}{2},\)则\(\cos \alpha +\cos \beta \)的取值范围_____.

              \((7)\)设数列\({{a}_{n}}\)满足:\({{a}_{1}}=\sqrt{3}\),\({{a}_{n+1}}=\left[ {{a}_{n}} \right]+\dfrac{1}{\left\{ {{a}_{n}} \right\}}\),其中,\(\left[ {{a}_{n}} \right]\)、\(\left\{ a{}_{n} \right\}\)分别表示正数\({{a}_{n}}\)的整数部分、小数部分,则\({{a}_{2018}}=\)_____.

            • 3. 若Sn是数列{an}的前n项和,且Sn=n2则{an}是(  )
              A.等比数列,但不是等差数列
              B.等差数列,但不是等比数列
              C.等差数列,而且也是等比数列
              D.既非等比数列又非等差数列
            • 4.
              已知等差数列\(\{a_{n}\}\)的前三项为\(a-1\),\(4\),\(2a\),记前\(n\)项和为\(S_{n}\).
              \((\)Ⅰ\()\)设\(S_{k}=2550\),求\(a\)和\(k\)的值;
              \((\)Ⅱ\()\)设\(b_{n}= \dfrac {S_{n}}{n}\),求\(b_{3}+b_{7}+b_{11}+…+b_{4n-1}\)的值.
            • 5.
              已知两个等差数列\(\{a_{n}\}\)和\(\{b_{n}\}\)的前\(n\)项和分别为\(A_{n}\)和\(B_{n}\),且\( \dfrac {A_{n}}{B_{n}}= \dfrac {7n+45}{n+3}\),则使得\( \dfrac {a_{n}}{b_{n}}\)为整数的正整数\(n\)的个数是\((\)  \()\)
              A.\(2\)
              B.\(3\)
              C.\(4\)
              D.\(5\)
            • 6.

              数列\(\{a_{n}\}\)满足\(a_{n+1}+(-1)^{n} a_{n} =2n-1\),则\(\{a_{n}\}\)的前\(60\)项和为________

            • 7. 已知数列\(\{ \)\(a_{n}\)\(\}\)中, \(a\)\({\,\!}_{1}=1\),\({a}_{n+1}= \dfrac{2{a}_{n}}{2+{a}_{n}} ( \)\(n\)\(∈N_{+}).\)
              \((\)Ⅰ\()\)求 \(a\)\({\,\!}_{2}\), \(a\)\({\,\!}_{3}\), \(a\)\({\,\!}_{4}\)的值,猜想数列\(\{ \)\(a_{n}\)\(\}\)的通项公式;
              \((\)Ⅱ\()\)运用\((\)Ⅰ\()\)中的猜想,写出用三段论证明数列\(\{\dfrac{1}{{a}_{{n}}}\}\)是等差数列时的大前提、小前提和结论.
            • 8. 已知数列\(\{a_{n}\}\)是公比为\(2\)的等比数列,且\(a_{2}\),\(a_{3}+1\),\(a_{4}\)成等差数列.
              \((I)\)求数列\(\{a_{n}\}\)的通项公式;
              \((II)\)记\(b_{n}=a_{n}+n\),求数列\(\{b_{n}\}\)的前\(n\)项和\(T_{n}\).
            • 9. 已知三角形的三条边成公差为2的等差数列,且它的最大角的正弦值为
              3
              2
              ,则这个三角形的面积为    
            • 10. 若数列{an}满足an=qn(q>0,n∈N*)则以下命题中正确的是    
              ①{a2n}是等比数列
              {
              1
              an
              }
              是等比数列
              ③lgan是等差数列
              ④{lgan2}是等差数列.
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