Cho hàm số f(x) có đạo hàm liên tục trên đoạn [0;1] , thỏa mãn f(1) = 5, \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa8qCaeaaca % WGMbWaaeWaaeaacaWG4baacaGLOaGaayzkaaGaaeizaiaadIhaaSqa % aiaaicdaaeaacaaIXaaaniabgUIiYdGccqGH9aqpcaaIXaGaaGOmaa % aa!41AE! \int\limits_0^1 {f\left( x \right){\rm{d}}x} = 12\). tính \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOsaiabg2 % da9maapehabaGaamiEaiqadAgagaqbamaabmaabaGaamiEaaGaayjk % aiaawMcaaiaabsgacaWG4baaleaacaaIWaaabaGaaGymaaqdcqGHRi % I8aaaa!4205! J = \int\limits_0^1 {xf'\left( x \right){\rm{d}}x} \)
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOsaiabg2 % da9maapehabaGaamiEaiqadAgagaqbamaabmaabaGaamiEaaGaayjk % aiaawMcaaiaabsgacaWG4baaleaacaaIWaaabaGaaGymaaqdcqGHRi % I8aaaa!4205! J = \int\limits_0^1 {xf'\left( x \right){\rm{d}}x} \) Đặt \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaiqaaqaabe % qaaiaadwhacqGH9aqpcaWG4baabaGaaeizaiaadAhacqGH9aqpceWG % MbGbauaadaqadaqaaiaadIhaaiaawIcacaGLPaaacaqGKbGaamiEaa % aacaGL7baacqGHshI3daGabaabaeqabaGaaeizaiaadwhacqGH9aqp % caqGKbGaamiEaaqaaiaadAhacqGH9aqpcaWGMbWaaeWaaeaacaWG4b % aacaGLOaGaayzkaaaaaiaawUhaaaaa!5016! \left\{ \begin{array}{l} u = x\\ {\rm{d}}v = f'\left( x \right){\rm{d}}x \end{array} \right. \Rightarrow \left\{ \begin{array}{l} {\rm{d}}u = {\rm{d}}x\\ v = f\left( x \right) \end{array} \right.\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOsaiabg2 % da9maaeiaabaGaamiEaiaadAgadaqadaqaaiaadIhaaiaawIcacaGL % PaaaaiaawIa7amaaDaaaleaacaaIWaaabaGaaGymaaaakiabgkHiTm % aapehabaGaamOzamaabmaabaGaamiEaaGaayjkaiaawMcaaiaabsga % caWG4baaleaacaaIWaaabaGaaGymaaqdcqGHRiI8aOGaeyypa0Jaam % OzamaabmaabaGaaGymaaGaayjkaiaawMcaaiabgkHiTmaapehabaGa % amOzamaabmaabaGaamiEaaGaayjkaiaawMcaaiaabsgacaWG4baale % aacaaIWaaabaGaaGymaaqdcqGHRiI8aOGaeyypa0JaaGynaiabgkHi % TiaaigdacaaIYaGaeyypa0JaeyOeI0IaaG4naaaa!5EDF! J = \left. {xf\left( x \right)} \right|_0^1 - \int\limits_0^1 {f\left( x \right){\rm{d}}x} = f\left( 1 \right) - \int\limits_0^1 {f\left( x \right){\rm{d}}x} = 5 - 12 = - 7\)
