Tính giới hạn: \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciiBaiaacM % gacaGGTbWaamWaaeaadaqadaqaaiaaigdacqGHsisldaWcaaqaaiaa % igdaaeaacaaIYaWaaWbaaSqabeaacaaIYaaaaaaaaOGaayjkaiaawM % caamaabmaabaGaaGymaiabgkHiTmaalaaabaGaaGymaaqaaiaaioda % daahaaWcbeqaaiaaikdaaaaaaaGccaGLOaGaayzkaaGaaiOlaiaac6 % cacaGGUaWaaeWaaeaacaaIXaGaeyOeI0YaaSaaaeaacaaIXaaabaGa % amOBamaaCaaaleqabaGaaGOmaaaaaaaakiaawIcacaGLPaaaaiaawU % facaGLDbaaaaa!4E05! \lim \left[ {\left( {1 - \frac{1}{{{2^2}}}} \right)\left( {1 - \frac{1}{{{3^2}}}} \right)...\left( {1 - \frac{1}{{{n^2}}}} \right)} \right]\) .
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Lời giải:
Báo saiXét dãy số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaaca % WG1bWaaSbaaSqaaiaad6gaaeqaaaGccaGLOaGaayzkaaaaaa!39A0! \left( {{u_n}} \right)\), với \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaBa % aaleaacaWGUbaabeaakiabg2da9maabmaabaGaaGymaiabgkHiTmaa % laaabaGaaGymaaqaaiaaikdadaahaaWcbeqaaiaaikdaaaaaaaGcca % GLOaGaayzkaaWaaeWaaeaacaaIXaGaeyOeI0YaaSaaaeaacaaIXaaa % baGaaG4mamaaCaaaleqabaGaaGOmaaaaaaaakiaawIcacaGLPaaaca % GGUaGaaiOlaiaac6cadaqadaqaaiaaigdacqGHsisldaWcaaqaaiaa % igdaaeaacaWGUbWaaWbaaSqabeaacaaIYaaaaaaaaOGaayjkaiaawM % caaaaa!4C6C! {u_n} = \left( {1 - \frac{1}{{{2^2}}}} \right)\left( {1 - \frac{1}{{{3^2}}}} \right)...\left( {1 - \frac{1}{{{n^2}}}} \right)\); \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOBaiabgw % MiZkaaikdacaGGSaGaaGPaVlaad6gacqGHiiIZcqWIvesPaaa!3F87! n \ge 2,\,n \in N \)
Ta có:
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaBa % aaleaacaaIYaaabeaakiabg2da9iaaigdacqGHsisldaWcaaqaaiaa % igdaaeaacaaIYaWaaWbaaSqabeaacaaIYaaaaaaakiabg2da9maala % aabaGaaG4maaqaaiaaisdaaaGaeyypa0ZaaSaaaeaacaaIYaGaey4k % aSIaaGymaaqaaiaaikdacaGGUaGaaGOmaaaaaaa!4532! {u_2} = 1 - \frac{1}{{{2^2}}} = \frac{3}{4} = \frac{{2 + 1}}{{2.2}}\);
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaBa % aaleaacaaIZaaabeaakiabg2da9maabmaabaGaaGymaiabgkHiTmaa % laaabaGaaGymaaqaaiaaikdadaahaaWcbeqaaiaaikdaaaaaaaGcca % GLOaGaayzkaaGaaiOlamaabmaabaGaaGymaiabgkHiTmaalaaabaGa % aGymaaqaaiaaiodadaahaaWcbeqaaiaaikdaaaaaaaGccaGLOaGaay % zkaaGaeyypa0ZaaSaaaeaacaaIZaaabaGaaGinaaaacaGGUaWaaSaa % aeaacaaI4aaabaGaaGyoaaaacqGH9aqpdaWcaaqaaiaaisdaaeaaca % aI2aaaaiabg2da9maalaaabaGaaG4maiabgUcaRiaaigdaaeaacaaI % YaGaaiOlaiaaiodaaaaaaa!51F7! {u_3} = \left( {1 - \frac{1}{{{2^2}}}} \right).\left( {1 - \frac{1}{{{3^2}}}} \right) = \frac{3}{4}.\frac{8}{9} = \frac{4}{6} = \frac{{3 + 1}}{{2.3}}\);
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaBa % aaleaacaaI0aaabeaakiabg2da9maabmaabaGaaGymaiabgkHiTmaa % laaabaGaaGymaaqaaiaaikdadaahaaWcbeqaaiaaikdaaaaaaaGcca % GLOaGaayzkaaGaaiOlamaabmaabaGaaGymaiabgkHiTmaalaaabaGa % aGymaaqaaiaaiodadaahaaWcbeqaaiaaikdaaaaaaaGccaGLOaGaay % zkaaWaaeWaaeaacaaIXaGaeyOeI0YaaSaaaeaacaaIXaaabaGaaGin % amaaCaaaleqabaGaaGOmaaaaaaaakiaawIcacaGLPaaacqGH9aqpda % WcaaqaaiaaiodaaeaacaaI0aaaaiaac6cadaWcaaqaaiaaiIdaaeaa % caaI5aaaaiaac6cadaWcaaqaaiaaigdacaaI1aaabaGaaGymaiaaiA % daaaGaeyypa0ZaaSaaaeaacaaI1aaabaGaaGioaaaacqGH9aqpdaWc % aaqaaiaaisdacqGHRaWkcaaIXaaabaGaaGOmaiaac6cacaaI0aaaaa % aa!5B61! {u_4} = \left( {1 - \frac{1}{{{2^2}}}} \right).\left( {1 - \frac{1}{{{3^2}}}} \right)\left( {1 - \frac{1}{{{4^2}}}} \right) = \frac{3}{4}.\frac{8}{9}.\frac{{15}}{{16}} = \frac{5}{8} = \frac{{4 + 1}}{{2.4}}\)
...
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaBa % aaleaacaWGUbaabeaakiabg2da9maalaaabaGaamOBaiabgUcaRiaa % igdaaeaacaaIYaGaamOBaaaaaaa!3D6C! {u_n} = \frac{{n + 1}}{{2n}}\)
Dễ dàng chứng minh bằng phương pháp qui nạp để khẳng định \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyDamaaBa % aaleaacaWGUbaabeaakiabg2da9maalaaabaGaamOBaiabgUcaRiaa % igdaaeaacaaIYaGaamOBaaaacaGGSaGaaGPaVlabgcGiIiaad6gacq % GHLjYScaaIYaaaaa!43EC! {u_n} = \frac{{n + 1}}{{2n}},\,\forall n \ge 2\)
Khi đó .
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaciiBaiaacM % gacaGGTbWaamWaaeaadaqadaqaaiaaigdacqGHsisldaWcaaqaaiaa % igdaaeaacaaIYaWaaWbaaSqabeaacaaIYaaaaaaaaOGaayjkaiaawM % caamaabmaabaGaaGymaiabgkHiTmaalaaabaGaaGymaaqaaiaaioda % daahaaWcbeqaaiaaikdaaaaaaaGccaGLOaGaayzkaaGaaiOlaiaac6 % cacaGGUaWaaeWaaeaacaaIXaGaeyOeI0YaaSaaaeaacaaIXaaabaGa % amOBamaaCaaaleqabaGaaGOmaaaaaaaakiaawIcacaGLPaaaaiaawU % facaGLDbaacqGH9aqpciGGSbGaaiyAaiaac2gadaWcaaqaaiaad6ga % cqGHRaWkcaaIXaaabaGaaGOmaiaad6gaaaGaeyypa0ZaaSaaaeaaca % aIXaaabaGaaGOmaaaaaaa!58B7! \lim \left[ {\left( {1 - \frac{1}{{{2^2}}}} \right)\left( {1 - \frac{1}{{{3^2}}}} \right)...\left( {1 - \frac{1}{{{n^2}}}} \right)} \right] = \lim \frac{{n + 1}}{{2n}} = \frac{1}{2}\)
Câu hỏi liên quan
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Khẳng định nào sau đây đúng:
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Nghiệm của phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaaeaaaaaaaaa8 % qaciGGJbGaai4BaiaacohacaWG4bGaeyypa0JaeyOeI0IaaGPaVlaa % cckadaWcaaqaaiaaigdaaeaacaaIYaaaaaaa!400C! \cos x = - \,\;\frac{1}{2}\) là :
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Cho hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaamiEaaGaayjkaiaawMcaaiabg2da9maaceaabaqbaeaabiWa % aaqaamaalaaabaWaaOaaaeaacaaIYaGaamiEaiabgUcaRiaaiIdaaS % qabaGccqGHsislcaaIYaaabaWaaOaaaeaacaWG4bGaey4kaSIaaGOm % aaWcbeaaaaaakeaacaqGRbGaaeiAaiaabMgaaeaacaWG4bGaeyOpa4 % JaeyOeI0IaaGOmaaqaaiaaicdaaeaacaqGRbGaaeiAaiaabMgaaeaa % caWG4bGaeyypa0JaeyOeI0IaaGOmaaaaaiaawUhaaaaa!512F! f\left( x \right) = \left\{ {\begin{array}{*{20}{l}} {\frac{{\sqrt {2x + 8} - 2}}{{\sqrt {x + 2} }}}&{{\rm{khi}}}&{x > - 2}\\ 0&{{\rm{khi}}}&{x = - 2} \end{array}} \right.\) . Tìm khẳng định đúng trong các khẳng định sau:
\((I)\) \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaCbeaeaaci % GGSbGaaiyAaiaac2gaaSqaaiaadIhacqGHsgIRdaqadaqaaiabgkHi % TiaaikdaaiaawIcacaGLPaaadaahaaadbeqaaiabgUcaRaaaaSqaba % GccaWGMbWaaeWaaeaacaWG4baacaGLOaGaayzkaaGaeyypa0JaaGim % aaaa!456E! \mathop {\lim }\limits_{x \to {{\left( { - 2} \right)}^ + }} f\left( x \right) = 0\) .
\((II)\) \(f(x)\) liên tục tại \(x=-2\).
\((III)\) \(f(x)\) gián đoạn tại \(x=-2\).
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Cho khối chóp S.ABC , trên ba cạnh SA,SB, SC lần lượt lấy ba điểm A' ,B' ,C' sao cho \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uaiqadg % eagaqbaiabg2da9maalaaabaGaaGymaaqaaiaaikdaaaGaam4uaiaa % dgeaaaa!3BC8! SA' = \frac{1}{2}SA\) ,\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uaiqadk % eagaqbaiabg2da9maalaaabaGaaGymaaqaaiaaiodaaaGaam4uaiaa % dkeaaaa!3BCB! SB' = \frac{1}{3}SB\) ,\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uaiqado % eagaqbaiabg2da9maalaaabaGaaGymaaqaaiaaisdaaaGaam4uaiaa % doeaaaa!3BCE! SC' = \frac{1}{4}SC\) . Gọi V và V' lần lượt là thể tích của các khối chóp S.ABC và S.A'B'C' . Khi đó tỉ số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaace % WGwbGbauaaaeaacaWGwbaaaaaa!37C5! \frac{{V'}}{V}\) là:
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Cho tứ diện ABCD có AB = AC và DB = DC. Khẳng định nào sau đây đúng?
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Một chất điểm chuyển động theo quy luật \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uamaabm % aabaGaamiDaaGaayjkaiaawMcaaiabg2da9iaaigdacqGHRaWkcaaI % ZaGaamiDamaaCaaaleqabaGaaGOmaaaakiabgkHiTiaadshadaahaa % Wcbeqaaiaaiodaaaaaaa!4169! S\left( t \right) = 1 + 3{t^2} - {t^3}\) . Vận tốc của chuyển động đạt giá trị lớn nhất khi t bằng bao nhiêu
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Cho một cấp số cộng \(\ \left( {{u_n}} \right)\) có \({u_1} = \frac{1}{3} ; u_8 = 26\) , Tìm công sai \( d\)
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Cho khối lăng trụ \(ABC.A'B'C'\) có thể tích là \(V\), thể tích của khối chóp \(C'.ABC\) là:
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Hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaamiEaaGaayjkaiaawMcaaiabg2da9maalaaabaGaamiEamaa % CaaaleqabaGaaGOmaaaakiabgUcaRiaadIhacqGHRaWkcaaIXaaaba % GaamiEaiabgUcaRiaaigdaaaaaaa!4281! f\left( x \right) = \frac{{{x^2} + x + 1}}{{x + 1}}\) có bao nhiêu điểm cực trị?
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Nghiệm của phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqamaaDa % aaleaacaWGUbaabaGaaG4maaaakiabg2da9iaaikdacaaIWaGaamOB % aaaa!3C0F! A_n^3 = 20n\) là:
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Trong các hàm số sau đây, hàm số nào là hàm số tuần hoàn?
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Cho hình chóp S.ABC có đáy là \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeuiLdqKaam % yqaiaadkeacaWGdbaaaa!39AE! \Delta ABC\) vuông cân ở B, \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqaiaado % eacqGH9aqpcaWGHbWaaOaaaeaacaaIYaaaleqaaOGaaiilaiaaykW7 % aaa!3C89! AC = a\sqrt 2 ,\,\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uaiaadg % eacqGHLkIxdaqadaqaaiaadgeacaWGcbGaam4qaaGaayjkaiaawMca % aiaacYcaaaa!3DD0! SA \bot \left( {ABC} \right),\) SA = a. Gọi G là trọng tâm của \(\Delta SBC\) , \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyBaiaadc % hadaqadaqaaiabeg7aHbGaayjkaiaawMcaaaaa!3B02! mp\left( \alpha \right)\) đi qua AG và song song với BC chia khối chóp thành hai phần. Gọi V là thể tích của khối đa diện không chứa đỉnh S. Tính V
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Cho lăng trụ ABC.A'B'C' có đáy là tam giác đều cạnh a. Hình chiếu vuông góc của điểm A' lên mặt phẳng (ABC) trùng với trọng tâm tam giác ABC. Biết khoảng cách giữa hai đường thẳng AA' và BC bằng \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca % WGHbWaaOaaaeaacaaIZaaaleqaaaGcbaGaaGinaaaaaaa!388A! \frac{{a\sqrt 3 }}{4}\). Khi đó thể tích của khối lăng trụ là
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Cho hai đường thẳng a và b chéo nhau. Có bao nhiêu mặt phẳng chứa a và song song với b ?
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Cho hình chóp đều S.ABC có cạnh đáy bằng a , góc giữa một mặt bên và mặt đáy bằng \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGOnaiaaic % dacqGHWcaSaaa!395A! 60^\circ \) . Tính độ dài đường cao SH.
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Cho lăng trụ đứng tam giác ABC.A'BC' có đáy là một tam giác vuông cân tại B, AB = BC = a,\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqaiqadg % eagaqbaiabg2da9iaadggadaGcaaqaaiaaikdaaSqabaaaaa!3A4F! AA' = a\sqrt 2\) , M là trung điểm BC . Tính khoảng cách giữa hai đường thẳng AM và B'C.
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Số mặt phẳng đối xứng của hình lập phương là:
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Thể tích của khối lăng trụ có diện tích đáy bằng B và chiều cao bằng h là:
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Đồ thị sau đây là của hàm số nào?
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Tìm hoành độ các giao điểm của đường thẳng \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9iaaikdacaWG4bGaeyOeI0YaaSaaaeaacaaIXaGaaG4maaqaaiaa % isdaaaaaaa!3CE3! y = 2x - \frac{{13}}{4}\) với đồ thị hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9maalaaabaGaamiEamaaCaaaleqabaGaaGOmaaaakiabgkHiTiaa % igdaaeaacaWG4bGaey4kaSIaaGOmaaaaaaa!3E3A! y = \frac{{{x^2} - 1}}{{x + 2}}\) .
