Cho hàm số f(x) thỏa mãn f'(x) = 3 - 5cosx và f(0)= 5 . Mệnh đề nào dưới đây đúng?
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Lời giải:
Báo saiTa có \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaamiEaaGaayjkaiaawMcaaiabg2da9maapeaabaWaaeWaaeaa % caaIZaGaeyOeI0IaaGynaiGacogacaGGVbGaai4CaiaadIhaaiaawI % cacaGLPaaaaSqabeqaniabgUIiYdGccaaMc8UaaeizaiaadIhacqGH % 9aqpcaaIZaGaamiEaiabgkHiTiaaiwdaciGGZbGaaiyAaiaac6gaca % WG4bGaey4kaSIaam4qaaaa!518B! f\left( x \right) = \int {\left( {3 - 5\cos x} \right)} \,{\rm{d}}x = 3x - 5\sin x + C\)
Lại có \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaaGimaaGaayjkaiaawMcaaiabg2da9iaaiwdacqGHuhY2caaI % ZaGaaiOlaiaaicdacqGHsislcaaI1aGaci4CaiaacMgacaGGUbGaaG % imaiabgUcaRiaadoeacqGH9aqpcaaI1aGaeyi1HSTaam4qaiabg2da % 9iaaiwdaaaa!4D01! f\left( 0 \right) = 5 \Leftrightarrow 3.0 - 5\sin 0 + C = 5 \Leftrightarrow C = 5\)
Vậy \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaamiEaaGaayjkaiaawMcaaiabg2da9iaaiodacaWG4bGaeyOe % I0IaaGynaiGacohacaGGPbGaaiOBaiaadIhacqGHRaWkcaaI1aaaaa!4346! f\left( x \right) = 3x - 5\sin x + 5\)