优优班--学霸训练营 > 知识点挑题
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            • 1.
              用数学归纳法证明“\(1+a+a^{2}+…+a^{2n+1}= \dfrac {1-a^{2n+2}}{1-a}\),\((a\neq 1)\)”,在验证\(n=1\)时,左端计算所得项为\((\)  \()\)
              A.\(1+a+a^{2}+a^{3}+a^{4}\)
              B.\(1+a\)
              C.\(1+a+a^{2}\)
              D.\(1+a+a^{2}+a^{3}\)
            • 2.
              用数学归纳法证明为:\(1+c+c^{2}+c^{3}+…+c^{n+1}= \dfrac {1-c^{n+2}}{1-c}(c\neq 1)\),当\(n=1\)时,左边为 ______ .
            • 3.
              已知\(S_{n}= \dfrac {1}{n+1}+ \dfrac {1}{n+2}+…+ \dfrac {1}{2n}\),\(n∈N*\),利用数学归纳法证明不等式\(S_{n} > \dfrac {13}{24}\)的过程中,从\(n=k\)到\(n=k+l(k∈N*)\)时,不等式的左边\(S_{k+1}=S_{k}+\) ______ .
            • 4.
              用数学归纳法证明\(1+2+3+…+n^{2}= \dfrac {n^{4}+n^{2}}{2}\),则当\(n=k+1\)时左端应在\(n=k\)的基础上加上\((\)  \()\)
              A.\(k^{2}+1\)
              B.\((k+1)^{2}\)
              C.\( \dfrac {(k+1)^{4}+(k+1)^{2}}{2}\)
              D.\((k^{2}+1)+(k^{2}+2)+(k^{2}+3)+…+(k+1)^{2}\)
            • 5.
              用数学归纳法证明不等式“\( \dfrac {1}{n+1}+ \dfrac {1}{n+2}+…+ \dfrac {1}{2n} > \dfrac {13}{24}(n > 2)\)”时的过程中,由\(n=k\)到\(n=k+1\),\((k > 2)\)时,不等式的左边\((\)  \()\)
              A.增加了一项\( \dfrac {1}{2(k+1)}\)
              B.增加了两项\( \dfrac {1}{2k+1}+ \dfrac {1}{2(k+1)}\)
              C.增加了一项\( \dfrac {1}{2(k+1)}\),又减少了一项\( \dfrac {1}{k+1}\)
              D.增加了两项\( \dfrac {1}{2k+1}+ \dfrac {1}{2(k+1)}\),又减少了一项\( \dfrac {1}{k+1}\)
            • 6.
              \((1)\)当\(x > 1\)时,求证:\(x^{2}+ \dfrac {1}{x^{2}} > x+ \dfrac {1}{x}\);
              \((2)\)用数学归纳法证明\( \dfrac {1}{n+1}+ \dfrac {1}{n+2}+…+ \dfrac {1}{3n}\geqslant \dfrac {5}{6}(n∈N^{*}).\)
            • 7.
              \(S_{n}\)是数列\(\{a_{n}\}\)前\(n\)项和,对\(∀n∈N^{*}\),\(S_{n}+a_{n}=2n\).
              \((1)\)求\(a_{1}\),\(a_{2}\),\(a_{3}\),\(a_{4}\);
              \((2)\)归纳数列\(\{a_{n}\}\)的通项公式,并用数学归纳法证明.
            • 8.
              在各项为正的数列\(\{a_{n}\}\)中,数列的前\(n\)项和\(S_{n}\)满足\(S_{n}= \dfrac {1}{2}(a_{n}+ \dfrac {1}{a_{n}})\),
              \((1)\)求\(a_{1}\),\(a_{2}\),\(a_{3}\);
              \((2)\)由\((1)\)猜想数列\(\{a_{n}\}\)的通项公式,并用数学归纳法证明你的猜想.
            • 9.
              已知数列\(\{a_{n}\}\)的各项均为正数,其前\(n\)项和为\(S_{n}\),首项\(a_{1}=1\),且\(S_{n}= \dfrac {1}{2}(a_{n}+ \dfrac {1}{a_{n}})\),\(n∈N^{*}\).
              \((1)\)求\(a_{2}\),\(a_{3}\),\(a_{4}\),\(a_{5}\)的值;
              \((2)\)试猜想数列\(\{a_{n}\}\)的通项公式,并用数学归纳法证明.
            • 10.
              已知数列\(\{a_{n}\}\)的前\(n\)项和\(S_{n}=1-na_{n}(n∈N^{*})\)
              \((1)\)计算\(a_{1}\),\(a_{2}\),\(a_{3}\),\(a_{4}\);
              \((2)\)猜想\(a_{n}\)的表达式,并用数学归纳法证明你的结论.
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