Biết \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa8qCaeaada % WcaaqaaiGacYgacaGGUbGaamiEaaqaamaakaaabaGaamiEaaWcbeaa % aaGccaqGKbGaamiEaaWcbaGaaGymaaqaaiaadwgaa0Gaey4kIipaki % abg2da9iaadggadaGcaaqaaiaadwgaaSqabaGccqGHRaWkcaWGIbaa % aa!44C6! \int\limits_1^e {\frac{{\ln x}}{{\sqrt x }}{\rm{d}}x} = a\sqrt e + b\) với a, b thuộc Z . Tính P = ab
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaiqaaqaabe % qaaiaadwhacqGH9aqpciGGSbGaaiOBaiaadIhaaeaacaqGKbGaamOD % aiabg2da9maalaaabaGaaeizaiaadIhaaeaadaGcaaqaaiaadIhaaS % qabaaaaaaakiaawUhaaiabgkziUoaaceaaeaqabeaacaqGKbGaamyD % aiabg2da9maalaaabaGaaeizaiaadIhaaeaacaWG4baaaaqaaiaabs % gacaWG2bGaeyypa0JaaGOmamaakaaabaGaamiEaaWcbeaaaaGccaGL % 7baaaaa!4F9F! \left\{ \begin{array}{l} u = \ln x\\ {\rm{d}}v = \frac{{{\rm{d}}x}}{{\sqrt x }} \end{array} \right. \to \left\{ \begin{array}{l} {\rm{d}}u = \frac{{{\rm{d}}x}}{x}\\ {\rm{d}}v = 2\sqrt x \end{array} \right.\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa8qCaeaada % WcaaqaaiGacYgacaGGUbGaamiEaaqaamaakaaabaGaamiEaaWcbeaa % aaGccaqGKbGaamiEaaWcbaGaaGymaaqaaiaadwgaa0Gaey4kIipaki % abg2da9maaeiaabaGaaGOmamaakaaabaGaamiEaaWcbeaakiGacYga % caGGUbGaamiEaaGaayjcSdWaa0baaSqaaiaaigdaaeaacaWGLbaaaO % GaeyOeI0IaaGOmamaapehabaWaaSaaaeaacaqGKbGaamiEaaqaamaa % kaaabaGaamiEaaWcbeaaaaaabaGaaGymaaqaaiaadwgaa0Gaey4kIi % pakiabg2da9maaeiaabaGaaGOmamaakaaabaGaamiEaaWcbeaakiGa % cYgacaGGUbGaamiEaaGaayjcSdWaa0baaSqaaiaaigdaaeaacaWGLb % aaaOGaeyOeI0IaaGinamaaeiaabaWaaOaaaeaacaWG4baaleqaaaGc % caGLiWoadaqhaaWcbaGaaGymaaqaaiaadwgaaaGccqGH9aqpcqGHsi % slcaaIYaWaaOaaaeaacaWGLbaaleqaaOGaey4kaSIaaGinaaaa!66CF! \int\limits_1^e {\frac{{\ln x}}{{\sqrt x }}{\rm{d}}x} = \left. {2\sqrt x \ln x} \right|_1^e - 2\int\limits_1^e {\frac{{{\rm{d}}x}}{{\sqrt x }}} = \left. {2\sqrt x \ln x} \right|_1^e - 4\left. {\sqrt x } \right|_1^e = - 2\sqrt e + 4\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyO0H49aai % qaaqaabeqaaiaadggacqGH9aqpcqGHsislcaaIYaaabaGaamOyaiab % g2da9iaaisdaaaGaay5Eaaaaaa!3FB1! \Rightarrow \left\{ \begin{array}{l} a = - 2\\ b = 4 \end{array} \right.\) . Vậy P = a.b = -8