Biết \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa8qCaeaaca % WG4bGaciiBaiaac6gadaqadaqaaiaadIhadaahaaWcbeqaaiaaikda % aaGccqGHRaWkcaaI5aaacaGLOaGaayzkaaGaaeizaiaadIhaaSqaai % aaicdaaeaacaaI0aaaniabgUIiYdGccqGH9aqpcaWGHbGaciiBaiaa % c6gacaaI1aGaey4kaSIaamOyaiGacYgacaGGUbGaaG4maiabgUcaRi % aadogaaaa!4E85! \int\limits_0^4 {x\ln \left( {{x^2} + 9} \right){\rm{d}}x} = a\ln 5 + b\ln 3 + c\), trong đó a,b ,c là các số nguyên. Giá trị của biểu thức T = a + b + c là
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Lời giải:
Báo saiĐặt \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaiqaaqaabe % qaaiaadwhacqGH9aqpciGGSbGaaiOBamaabmaabaGaamiEamaaCaaa % leqabaGaaGOmaaaakiabgUcaRiaaiMdaaiaawIcacaGLPaaaaeaaca % qGKbGaamODaiabg2da9iaadIhacaqGKbGaamiEaaaacaGL7baacqGH % uhY2daGabaabaeqabaGaaeizaiaadwhacqGH9aqpdaWcaaqaaiaaik % dacaWG4baabaWaaeWaaeaacaWG4bWaaWbaaSqabeaacaaIYaaaaOGa % ey4kaSIaaGyoaaGaayjkaiaawMcaaaaacaqGKbGaamiEaaqaaiaadA % hacqGH9aqpdaWcaaqaaiaadIhadaahaaWcbeqaaiaaikdaaaGccqGH % RaWkcaaI5aaabaGaaGOmaaaaaaGaay5Eaaaaaa!5B70! \left\{ \begin{array}{l} u = \ln \left( {{x^2} + 9} \right)\\ {\rm{d}}v = x{\rm{d}}x \end{array} \right. \Leftrightarrow \left\{ \begin{array}{l} {\rm{d}}u = \frac{{2x}}{{\left( {{x^2} + 9} \right)}}{\rm{d}}x\\ v = \frac{{{x^2} + 9}}{2} \end{array} \right.\)
Suy ra \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa8qCaeaaca % WG4bGaciiBaiaac6gadaqadaqaaiaadIhadaahaaWcbeqaaiaaikda % aaGccqGHRaWkcaaI5aaacaGLOaGaayzkaaGaaeizaiaadIhaaSqaai % aaicdaaeaacaaI0aaaniabgUIiYdGccqGH9aqpdaabcaqaamaalaaa % baGaamiEamaaCaaaleqabaGaaGOmaaaakiabgUcaRiaaiMdaaeaaca % aIYaaaaiGacYgacaGGUbWaaeWaaeaacaWG4bWaaWbaaSqabeaacaaI % YaaaaOGaey4kaSIaaGyoaaGaayjkaiaawMcaaaGaayjcSdWaa0baaS % qaaiaaicdaaeaacaaI0aaaaOGaeyOeI0Yaa8qCaeaadaWcaaqaaiaa % dIhadaahaaWcbeqaaiaaikdaaaGccqGHRaWkcaaI5aaabaGaaGOmaa % aacaGGUaWaaSaaaeaacaaIYaGaamiEaaqaaiaadIhadaahaaWcbeqa % aiaaikdaaaGccqGHRaWkcaaI5aaaaiaabsgacaWG4baaleaacaaIWa % aabaGaaGinaaqdcqGHRiI8aaaa!6492! \int\limits_0^4 {x\ln \left( {{x^2} + 9} \right){\rm{d}}x} = \left. {\frac{{{x^2} + 9}}{2}\ln \left( {{x^2} + 9} \right)} \right|_0^4 - \int\limits_0^4 {\frac{{{x^2} + 9}}{2}.\frac{{2x}}{{{x^2} + 9}}{\rm{d}}x} \)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyypa0JaaG % OmaiaaiwdaciGGSbGaaiOBaiaaiwdacqGHsislcaaI5aGaciiBaiaa % c6gacaaIZaGaeyOeI0IaaGioaaaa!4118! = 25\ln 5 - 9\ln 3 - 8\)
Do đó a = 25,b = -9 , c = - 8 nên T =8 .
Đề thi thử tốt nghiệp THPT QG môn Toán năm 2020
Tuyển chọn số 2