Điều kiện xác định của bất phương trình \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaai4BaiaacE % gadaWgaaWcbaWaaSaaaeaacaaIXaaabaGaaGOmaaaaaeqaaOWaamWa % aeaaciGGSbGaai4BaiaacEgadaWgaaWcbaGaaGOmaaqabaGccaGGOa % GaaGOmaiabgkHiTiaadIhadaahaaWcbeqaaiaaikdaaaGccaGGPaaa % caGLBbGaayzxaaGaeyOpa4JaaGimaaaa!45F7! lo{g_{\frac{1}{2}}}\left[ {{{\log }_2}(2 - {x^2})} \right] > 0\) là:
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Lời giải:
Báo saiBPT xác định khi : \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaiqaaqaabe % qaaiaaikdacqGHsislcaWG4bWaaWbaaSqabeaacaaIYaaaaOGaeyOp % a4JaaGimaaqaaiGacYgacaGGVbGaai4zamaaBaaaleaacaaIYaaabe % aakiaacIcacaaIYaGaeyOeI0IaamiEamaaCaaaleqabaGaaGOmaaaa % kiaacMcacqGH+aGpcaaIWaaaaiaawUhaaiabgsDiBpaaceaaeaqabe % aacqGHsisldaGcaaqaaiaaikdaaSqabaGccqGH8aapcaWG4bGaeyip % aWZaaOaaaeaacaaIYaaaleqaaaGcbaGaaGOmaiabgkHiTiaadIhada % ahaaWcbeqaaiaaikdaaaGccqGH+aGpcaaIXaaaaiaawUhaaiabgsDi % BpaaceaaeaqabeaacqGHsisldaGcaaqaaiaaikdaaSqabaGccqGH8a % apcaWG4bGaeyipaWZaaOaaaeaacaaIYaaaleqaaaGcbaGaaGymaiab % gkHiTiaadIhadaahaaWcbeqaaiaaikdaaaGccqGH+aGpcaaIWaaaai % aawUhaaaaa!63FD! \left\{ \begin{array}{l} 2 - {x^2} > 0\\ {\log _2}(2 - {x^2}) > 0 \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} - \sqrt 2 < x < \sqrt 2 \\ 2 - {x^2} > 1 \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} - \sqrt 2 < x < \sqrt 2 \\ 1 - {x^2} > 0 \end{array} \right.\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyi1HS9aai % qaaqaabeqaaiabgkHiTmaakaaabaGaaGOmaaWcbeaakiabgYda8iaa % dIhacqGH8aapdaGcaaqaaiaaikdaaSqabaaakeaacqGHsislcaaIXa % GaeyipaWJaamiEaiabgYda8iaaigdaaaGaay5EaaGaeyi1HSTaeyOe % I0IaaGymaiabgYda8iaadIhacqGH8aapcaaIXaaaaa!4C50! \Leftrightarrow \left\{ \begin{array}{l} - \sqrt 2 < x < \sqrt 2 \\ - 1 < x < 1 \end{array} \right. \Leftrightarrow - 1 < x < 1\)