Cho hàm số y =f(x) có \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa8qaaeaaca % WGMbWaaeWaaeaacaWG4baacaGLOaGaayzkaaGaaeizaiaadIhaaSqa % beqaniabgUIiYdGccqGH9aqpcaWG4bGaci4CaiaacMgacaGGUbGaam % iEaiabgUcaRiaadoeaaaa!44D0! \int {f\left( x \right){\rm{d}}x} = x\sin x + C\). Tính \(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaWaaSaaaeaacqaHapaCaeaacaaIYaaaaaGaayjkaiaawMcaaaaa % !3AF1! f\left( {\frac{\pi }{2}} \right)\).
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabm % aabaGaamiEaaGaayjkaiaawMcaaiabg2da9maabmaabaGaamiEaiGa % cohacaGGPbGaaiOBaiaadIhacqGHRaWkcaWGdbaacaGLOaGaayzkaa % WaaWbaaSqabeaakiadacUHYaIOaaGaeyypa0Jaci4CaiaacMgacaGG % UbGaamiEaiabgUcaRiaadIhaciGGJbGaai4BaiaacohacaWG4baaaa!5019! f\left( x \right) = {\left( {x\sin x + C} \right)^\prime } = \sin x + x\cos x\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyO0H4Taam % OzamaabmaabaWaaSaaaeaacqaHapaCaeaacaaIYaaaaaGaayjkaiaa % wMcaaiabg2da9iaaigdaaaa!3F0F! \Rightarrow f\left( {\frac{\pi }{2}} \right) = 1\)