Tính đạo hàm của hàm số sau: \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiabg2 % da9maabmaabaGaci4yaiaac+gacaGGZbWaaWbaaSqabeaacaaI0aaa % aOGaamiEaiabgkHiTiGacohacaGGPbGaaiOBamaaCaaaleqabaGaaG % inaaaakiaadIhaaiaawIcacaGLPaaadaahaaWcbeqaaiaaiwdaaaaa % aa!44E9! y = {\left( {{{\cos }^4}x - {{\sin }^4}x} \right)^5}\)
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyypa0Zaam % WaaeaadaqadaqaaiGacogacaGGVbGaai4CamaaCaaaleqabaGaaGOm % aaaakiaadIhacqGHsislciGGZbGaaiyAaiaac6gadaahaaWcbeqaai % aaikdaaaGccaWG4baacaGLOaGaayzkaaWaaeWaaeaaciGGJbGaai4B % aiaacohadaahaaWcbeqaaiaaikdaaaGccaWG4bGaey4kaSIaci4Cai % aacMgacaGGUbWaaWbaaSqabeaacaaIYaaaaOGaamiEaaGaayjkaiaa % wMcaaaGaay5waiaaw2faamaaCaaaleqabaGaaGynaaaakiabg2da9m % aabmaabaGaci4yaiaac+gacaGGZbGaaGOmaiaadIhaaiaawIcacaGL % PaaadaahaaWcbeqaaiaaiwdaaaGccaGGUaaaaa!5A9C! = {\left[ {\left( {{{\cos }^2}x - {{\sin }^2}x} \right)\left( {{{\cos }^2}x + {{\sin }^2}x} \right)} \right]^5} = {\left( {\cos 2x} \right)^5}.\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyEaiaacE % cacqGH9aqpcaaI1aGaaiOlaiGacogacaGGVbGaai4CamaaCaaaleqa % baGaaGinaaaakiaaikdacaWG4bGaaiOlamaabmaabaGaci4yaiaac+ % gacaGGZbGaaGOmaiaadIhaaiaawIcacaGLPaaadaahaaWcbeqaaiaa % c+caaaGccqGH9aqpcaaI1aGaaiOlaiGacogacaGGVbGaai4CamaaCa % aaleqabaGaaGinaaaakiaaikdacaWG4bGaaiOlamaabmaabaGaeyOe % I0Iaci4CaiaacMgacaGGUbGaaGOmaiaadIhaaiaawIcacaGLPaaaca % GGUaWaaeWaaeaacaaIYaGaamiEaaGaayjkaiaawMcaamaaCaaaleqa % baGaai4laaaakiabg2da9iabgkHiTiaaigdacaaIWaGaci4yaiaac+ % gacaGGZbWaaWbaaSqabeaacaaI0aaaaOGaaGOmaiaadIhacaGGUaGa % ci4CaiaacMgacaGGUbGaaGOmaiaadIhacaGGUaaaaa!6AB3! y' = 5.{\cos ^4}2x.{\left( {\cos 2x} \right)^/} = 5.{\cos ^4}2x.\left( { - \sin 2x} \right).{\left( {2x} \right)^/} = - 10{\cos ^4}2x.\sin 2x.\)