\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaiaacI % cacaWG4bGaaiykaiabg2da9maaceaaeaqabeaacaaIYaGaamiEaiab % gUcaRiaaiodacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccaca % qGGaGaaeiiaiaabccacaqGGaGaaeiiaiaabccacaqGGaGaaeiiaiaa % bccacaqGGaGaaeiiaiaadUgacaWGObGaamyAaiaabccacaWG4bGaey % yzImRaaGymaaqaamaalaaabaGaamiEamaaCaaaleqabaGaaG4maaaa % kiabgUcaRiaaikdacaWG4bWaaWbaaSqabeaacaaIYaaaaOGaeyOeI0 % IaaG4naiaadIhacqGHRaWkcaaI0aaabaGaamiEaiabgkHiTiaaigda % aaGaaeiiaiaabUgacaqGObGaaeyAaiaabccacaWG4bGaeyipaWJaaG % ymaaaacaGL7baaaaa!63B9! f(x) = \left\{ \begin{array}{l} 2x + 3{\rm{ }}khi{\rm{ }}x \ge 1\\ \frac{{{x^3} + 2{x^2} - 7x + 4}}{{x - 1}}{\rm{ khi }}x < 1 \end{array} \right.\) tại \(x_0 = 1\)
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Lời giải:
Báo saiTa có \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaCbeaeaaci % GGSbGaaiyAaiaac2gaaSqaaiaadIhacqGHsgIRcaaIXaWaaWbaaWqa % beaacqGHRaWkaaaaleqaaOGaamOzaiaacIcacaWG4bGaaiykaiabg2 % da9maaxababaGaciiBaiaacMgacaGGTbaaleaacaWG4bGaeyOKH4Qa % aGymamaaCaaameqabaGaey4kaScaaaWcbeaakmaabmaabaGaaGOmai % aadIhacqGHRaWkcaaIZaaacaGLOaGaayzkaaGaeyypa0JaaGynaaaa % !5087! \mathop {\lim }\limits_{x \to {1^ + }} f(x) = \mathop {\lim }\limits_{x \to {1^ + }} \left( {2x + 3} \right) = 5\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaCbeaeaaci % GGSbGaaiyAaiaac2gaaSqaaiaadIhacqGHsgIRcaaIXaWaaWbaaWqa % beaacqGHsislaaaaleqaaOGaamOzaiaacIcacaWG4bGaaiykaiabg2 % da9maaxababaGaciiBaiaacMgacaGGTbaaleaacaWG4bGaeyOKH4Qa % aGymamaaCaaameqabaGaeyOeI0caaaWcbeaakmaalaaabaGaamiEam % aaCaaaleqabaGaaG4maaaakiabgUcaRiaaikdacaWG4bWaaWbaaSqa % beaacaaIYaaaaOGaeyOeI0IaaG4naiaadIhacqGHRaWkcaaI0aaaba % GaamiEaiabgkHiTiaaigdaaaGaeyypa0ZaaCbeaeaaciGGSbGaaiyA % aiaac2gaaSqaaiaadIhacqGHsgIRcaaIXaWaaWbaaWqabeaacqGHsi % slaaaaleqaaOGaaiikaiaadIhadaahaaWcbeqaaiaaikdaaaGccqGH % RaWkcaaIZaGaamiEaiabgkHiTiaaisdacaGGPaGaeyypa0JaaGimaa % aa!68AA! \mathop {\lim }\limits_{x \to {1^ - }} f(x) = \mathop {\lim }\limits_{x \to {1^ - }} \frac{{{x^3} + 2{x^2} - 7x + 4}}{{x - 1}} = \mathop {\lim }\limits_{x \to {1^ - }} ({x^2} + 3x - 4) = 0\)
Dẫn tới \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaCbeaeaaci % GGSbGaaiyAaiaac2gaaSqaaiaadIhacqGHsgIRcaaIXaWaaWbaaWqa % beaacqGHRaWkaaaaleqaaOGaamOzaiaacIcacaWG4bGaaiykaiabgc % Mi5oaaxababaGaciiBaiaacMgacaGGTbaaleaacaWG4bGaeyOKH4Qa % aGymamaaCaaameqabaGaeyOeI0caaaWcbeaakiaadAgacaGGOaGaam % iEaiaacMcacqGHshI3aaa!504B! \mathop {\lim }\limits_{x \to {1^ + }} f(x) \ne \mathop {\lim }\limits_{x \to {1^ - }} f(x) \Rightarrow \) hàm số không liên tục tại x = 1 nên hàm số không có đạo hàm tại \(x_0 = 1\).
