Hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9maabmaabaGaaGinaiabgkHiTiaadIhadaahaaWcbeqaaiaaikda % aaaakiaawIcacaGLPaaadaahaaWcbeqaaiaaikdaaaGccqGHRaWkca % aIXaaaaa!3FAB! y = {\left( {4 - {x^2}} \right)^2} + 1\) có giá trị lớn nhất trên đoạn \([-1; 1]\) là:
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Lời giải:
Báo saiTa có: \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmyEayaafa % Gaeyypa0JaaGinaiaadIhadaahaaWcbeqaaiaaiodaaaGccqGHsisl % caaIXaGaaGOnaiaadIhaaaa!3E17! y' = 4{x^3} - 16x\), cho \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmyEayaafa % Gaeyypa0JaaGimaiabgkDiElaaisdacaWG4bWaaWbaaSqabeaacaaI % ZaaaaOGaeyOeI0IaaGymaiaaiAdacaWG4bGaeyypa0JaaGimaiabgs % DiBpaadeaaeaqabeaacaWG4bGaeyypa0JaeyOeI0IaaGOmaiabgMGi % ppaadmaabaGaeyOeI0IaaGymaiaacUdacaaIXaaacaGLBbGaayzxaa % aabaGaamiEaiabg2da9iaaikdacqGHjiYZdaWadaqaaiabgkHiTiaa % igdacaGG7aGaaGymaaGaay5waiaaw2faaaqaaiaadIhacqGH9aqpca % aIWaGaeyicI48aamWaaeaacqGHsislcaaIXaGaai4oaiaaigdaaiaa % wUfacaGLDbaaaaGaay5waaaaaa!6341! y' = 0 \Rightarrow 4{x^3} - 16x = 0 \Leftrightarrow \left[ \begin{array}{l} x = - 2 \notin \left[ { - 1;1} \right]\\ x = 2 \notin \left[ { - 1;1} \right]\\ x = 0 \in \left[ { - 1;1} \right] \end{array} \right.\)
Khi đó: \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaeyOeI0IaaGymaaGaayjkaiaawMcaaiabg2da9iaaigdacaaI % Waaaaa!3C8A! f\left( { - 1} \right) = 10\), \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaaGymaaGaayjkaiaawMcaaiabg2da9iaaigdacaaIWaaaaa!3B9D! f\left( 1 \right) = 10\),\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaaGimaaGaayjkaiaawMcaaiabg2da9iaaigdacaaI3aaaaa!3BA3! f\left( 0 \right) = 17\) .
Vậy \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaCbeaeaaci % GGTbGaaiyyaiaacIhaaSqaamaadmaabaGaeyOeI0IaaGymaiaacUda % caaIXaaacaGLBbGaayzxaaaabeaakiaadMhacqGH9aqpcaWGMbWaae % WaaeaacaaIWaaacaGLOaGaayzkaaGaeyypa0JaaGymaiaaiEdaaaa!45D2! \mathop {\max }\limits_{\left[ { - 1;1} \right]} y = f\left( 0 \right) = 17\).
Đề thi thử tốt nghiệp THPT QG môn Toán năm 2020
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