Cho hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9iaadAgadaqadaqaaiaadIhaaiaawIcacaGLPaaacqGH9aqpciGG % ZbGaaiyAaiaac6gadaahaaWcbeqaaiaaiodaaaGccaaI1aGaamiEai % aac6caciGGJbGaai4BaiaacohadaahaaWcbeqaaiaaikdaaaGcdaWc % aaqaaiaadIhaaeaacaaIZaaaaaaa!4839! y = f\left( x \right) = {\sin ^3}5x.{\cos ^2}\frac{x}{3}\). Giá trị đúng của \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmOzayaafa % WaaeWaaeaadaWcaaqaaiabec8aWbqaaiaaikdaaaaacaGLOaGaayzk % aaaaaa!3AFD! f'\left( {\frac{\pi }{2}} \right)\) bằng
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzaiaacE % cadaqadaqaaiaadIhaaiaawIcacaGLPaaacqGH9aqpcaaIZaGaaiOl % aiaaiwdacaGGUaGaci4yaiaac+gacaGGZbGaaGynaiaadIhacaGGUa % Gaci4CaiaacMgacaGGUbWaaWbaaSqabeaacaaIYaaaaOGaaGynaiaa % dIhacaGGUaGaci4yaiaac+gacaGGZbWaaWbaaSqabeaacaaIYaaaaO % WaaSaaaeaacaWG4baabaGaaG4maaaacqGHsislciGGZbGaaiyAaiaa % c6gadaahaaWcbeqaaiaaiodaaaGccaaI1aGaamiEaiabgwSixpaala % aabaGaaGOmaaqaaiaaiodaaaGaeyyXICTaci4CaiaacMgacaGGUbWa % aSaaaeaacaWG4baabaGaaG4maaaacqGHflY1ciGGJbGaai4Baiaaco % hadaWcaaqaaiaadIhaaeaacaaIZaaaaaaa!671B! f'\left( x \right) = 3.5.\cos 5x.{\sin ^2}5x.{\cos ^2}\frac{x}{3} - {\sin ^3}5x \cdot \frac{2}{3} \cdot \sin \frac{x}{3} \cdot \cos \frac{x}{3}\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmOzayaafa % WaaeWaaeaadaWcaaqaaiabec8aWbqaaiaaikdaaaaacaGLOaGaayzk % aaGaeyypa0JaaGimaiabgkHiTiaaigdacaGGUaWaaSaaaeaadaGcaa % qaaiaaiodaaSqabaaakeaacaaIYaGaaiOlaiaaiodaaaGaeyypa0Ja % eyOeI0YaaSaaaeaadaGcaaqaaiaaiodaaSqabaaakeaacaaI2aaaai % abgwSixdaa!4823! f'\left( {\frac{\pi }{2}} \right) = 0 - 1.\frac{{\sqrt 3 }}{{2.3}} = - \frac{{\sqrt 3 }}{6} \cdot \)