\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaiaacI % cacaWG4bGaaiykaiabg2da9maaceaaeaqabeaadaWcaaqaamaakaaa % baGaamiEamaaCaaaleqabaGaaG4maaaakiabgkHiTiaaikdacaWG4b % WaaWbaaSqabeaacaaIYaaaaOGaey4kaSIaamiEaiabgUcaRiaaigda % aSqabaGccqGHsislcaaIXaaabaGaamiEaiabgkHiTiaaigdaaaGaae % iiaiaabccacaqGRbGaaeiAaiaabMgacaqGGaGaaeiiaiaadIhacqGH % GjsUcaaIXaaabaGaaGimaiaabccacaqGGaGaaeiiaiaabccacaqGGa % GaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabcca % caqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiai % aabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGRbGa % aeiAaiaabMgacaqGGaGaamiEaiabg2da9iaaigdaaaGaay5Eaaaaaa!6A68! f(x) = \left\{ \begin{array}{l} \frac{{\sqrt {{x^3} - 2{x^2} + x + 1} - 1}}{{x - 1}}{\rm{ khi }}x \ne 1\\ 0{\rm{ khi }}x = 1 \end{array} \right.\) tại điểm \(x_0 = 1\)
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaCbeaeaaci % GGSbGaaiyAaiaac2gaaSqaaiaadIhacqGHsgIRcaaIXaaabeaakmaa % laaabaGaamOzaiaacIcacaWG4bGaaiykaiabgkHiTiaadAgacaGGOa % GaaGymaiaacMcaaeaacaWG4bGaeyOeI0IaaGymaaaacqGH9aqpdaWf % qaqaaiGacYgacaGGPbGaaiyBaaWcbaGaamiEaiabgkziUkaaigdaae % qaaOWaaSaaaeaadaGcaaqaaiaadIhadaahaaWcbeqaaiaaiodaaaGc % cqGHsislcaaIYaGaamiEamaaCaaaleqabaGaaGOmaaaakiabgUcaRi % aadIhacqGHRaWkcaaIXaaaleqaaOGaeyOeI0IaaGymaaqaaiaacIca % caWG4bGaeyOeI0IaaGymaiaacMcadaahaaWcbeqaaiaaikdaaaaaaO % Gaeyypa0ZaaCbeaeaaciGGSbGaaiyAaiaac2gaaSqaaiaadIhacqGH % sgIRcaaIXaaabeaakmaalaaabaGaamiEaaqaamaakaaabaGaamiEam % aaCaaaleqabaGaaG4maaaakiabgkHiTiaaikdacaWG4bWaaWbaaSqa % beaacaaIYaaaaOGaey4kaSIaamiEaiabgUcaRiaaigdaaSqabaGccq % GHRaWkcaaIXaaaaiabg2da9maalaaabaGaaGymaaqaaiaaikdaaaaa % aa!7440! \mathop {\lim }\limits_{x \to 1} \frac{{f(x) - f(1)}}{{x - 1}} = \mathop {\lim }\limits_{x \to 1} \frac{{\sqrt {{x^3} - 2{x^2} + x + 1} - 1}}{{{{(x - 1)}^2}}} = \mathop {\lim }\limits_{x \to 1} \frac{x}{{\sqrt {{x^3} - 2{x^2} + x + 1} + 1}} = \frac{1}{2}\)
Vậy \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaiaacE % cacaGGOaGaaGymaiaacMcacqGH9aqpdaWcaaqaaiaaigdaaeaacaaI % Yaaaaaaa!3C2B! f'(1) = \frac{1}{2}\)