Gọi \(x_1; x_2\) là hai điểm cực trị của hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaiaacI % cacaWG4bGaaiykaiabg2da9maalaaabaGaaGymaaqaaiaaiodaaaGa % amiEamaaCaaaleqabaGaaG4maaaakiabgUcaRiaadIhadaahaaWcbe % qaaiaaikdaaaGccqGHsislcaaIZaGaamiEaiabgUcaRiaaigdaaaa!44C9! f(x) = \frac{1}{3}{x^3} + {x^2} - 3x + 1\). giá trị của \(x_1^3+x_2^3\) bằng
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGceaqabeaaqaaaaa % aaaaWdbiaadAgacaGGOaGaamiEaiaacMcacqGH9aqpdaWcaaWdaeaa % peGaaGymaaWdaeaapeGaaG4maaaacaWG4bWdamaaCaaaleqabaWdbi % aaiodaaaGccqGHRaWkcaWG4bWdamaaCaaaleqabaWdbiaaikdaaaGc % cqGHsislcaaIZaGaamiEaiabgUcaRiaaigdaaeaacaWGMbGaai4jai % aacIcacaWG4bGaaiykaiabg2da9iaadIhadaahaaWcbeqaaiaaikda % aaGccqGHRaWkcaaIYaGaamiEaiabgkHiTiaaiodacqGH9aqpcaaIWa % Gaeyi1HS9aamqaaqaabeqaaiaadIhadaWgaaWcbaGaaGymaaqabaGc % cqGH9aqpcqGHsislcaaIZaaabaGaamiEamaaBaaaleaacaaIYaaabe % aakiabg2da9iaaigdaaaGaay5waaaaaaa!5DFF! \begin{array}{l} f(x) = \frac{1}{3}{x^3} + {x^2} - 3x + 1\\ f'(x) = {x^2} + 2x - 3 = 0 \Leftrightarrow \left[ \begin{array}{l} {x_1} = - 3\\ {x_2} = 1 \end{array} \right. \end{array}\)
Vậy \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcqaaaaaaaaaWdbe % aacaWG4bWaa0baaSqaaiaaigdaaeaacaaIZaaaaOGaey4kaSIaamiE % amaaDaaaleaacaaIYaaabaGaaG4maaaakiabg2da9iabgkHiTiaaik % dacaaI2aaaaa!3FBD! x_1^3 + x_2^3 = - 26\)
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