Cho hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaiaacI % cacaWG4bGaaiykaiabg2da9iaadUgacaGGUaWaaOqaaeaacaWG4baa % leaacaaIZaaaaOGaey4kaSYaaOaaaeaacaWG4baaleqaaaaa!3FB5! f(x) = k.\sqrt[3]{x} + \sqrt x \). Với giá trị nào của k thì \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmOzayaafa % GaaiikaiaaigdacaGGPaGaeyypa0ZaaSaaaeaacaaIZaaabaGaaGOm % aaaaaaa!3B8D! f'(1) = \frac{3}{2}\)?
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmOzayaafa % GaaiikaiaadIhacaGGPaGaeyypa0ZaaeWaaeaacaWGRbGaaiOlaiaa % dIhadaahaaWcbeqaamaalaaabaGaaGymaaqaaiaaiodaaaaaaOGaey % 4kaSYaaOaaaeaacaWG4baaleqaaaGccaGLOaGaayzkaaWaaWbaaSqa % beaakiadacUHYaIOaaGaeyypa0Jaam4Aaiaac6cadaWcaaqaaiaaig % daaeaacaaIZaaaaiaac6cadaWcaaqaaiaaigdaaeaadaGcbaqaaiaa % dIhadaahaaWcbeqaaiaaikdaaaaabaGaaG4maaaaaaGccqGHRaWkda % WcaaqaaiaaigdaaeaacaaIYaWaaOaaaeaacaWG4baaleqaaaaaaaa!513B! f'(x) = {\left( {k.{x^{\frac{1}{3}}} + \sqrt x } \right)^\prime } = k.\frac{1}{3}.\frac{1}{{\sqrt[3]{{{x^2}}}}} + \frac{1}{{2\sqrt x }}\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmOzayaafa % GaaiikaiaaigdacaGGPaGaeyypa0ZaaSaaaeaacaaIZaaabaGaaGOm % aaaacqGHuhY2daWcaaqaaiaaigdaaeaacaaIZaaaaiaadUgacqGHRa % WkdaWcaaqaaiaaigdaaeaacaaIYaaaaiabg2da9maalaaabaGaaG4m % aaqaaiaaikdaaaGaeyi1HS9aaSaaaeaacaaIXaaabaGaaG4maaaaca % WGRbGaeyypa0JaaGymaiabgsDiBlaadUgacqGH9aqpcaaIZaaaaa!50FD! f'(1) = \frac{3}{2} \Leftrightarrow \frac{1}{3}k + \frac{1}{2} = \frac{3}{2} \Leftrightarrow \frac{1}{3}k = 1 \Leftrightarrow k = 3\)