Tính tích phân \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamysaiabg2 % da9maapehabaGaamiEaiaac6caciGGJbGaai4BaiaacohacaWG4bGa % aeizaiaadIhaaSqaaiaaicdaaeaadaWcaaqaaiabec8aWbqaaiaaik % daaaaaniabgUIiYdaaaa!44D6! I = \int\limits_0^{\frac{\pi }{2}} {x.\cos x{\rm{d}}x} \)
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Lời giải:
Báo sai\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaiqaaqaabe % qaaiaadwhacqGH9aqpcaWG4baabaGaaeizaiaadAhacqGH9aqpciGG % JbGaai4BaiaacohacaWG4bGaaeizaiaadIhaaaGaay5EaaGaeyO0H4 % 9aaiqaaqaabeqaaiaabsgacaWG1bGaeyypa0JaaeizaiaadIhaaeaa % caWG2bGaeyypa0Jaci4CaiaacMgacaGGUbGaamiEaaaacaGL7baaaa % a!50CC! \left\{ \begin{array}{l} u = x\\ {\rm{d}}v = \cos x{\rm{d}}x \end{array} \right. \Rightarrow \left\{ \begin{array}{l} {\rm{d}}u = {\rm{d}}x\\ v = \sin x \end{array} \right.\)
\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamysaiabg2 % da9maapehabaGaamiEaiaac6caciGGJbGaai4BaiaacohacaWG4bGa % aeizaiaadIhaaSqaaiaaicdaaeaadaWcaaqaaiabec8aWbqaaiaaik % daaaaaniabgUIiYdGccqGH9aqpcaWG4bGaci4CaiaacMgacaGGUbGa % amiEamaaeeaabaWaa0baaSqaaiaaicdaaeaadaWcaaqaaiabec8aWb % qaaiaaikdaaaaaaaGccaGLhWoacqGHsisldaWdXbqaaiGacohacaGG % PbGaaiOBaiaadIhacaqGKbGaamiEaiabg2da9maalaaabaGaeqiWda % habaGaaGOmaaaaaSqaaiaaicdaaeaadaWcaaqaaiabec8aWbqaaiaa % ikdaaaaaniabgUIiYdGccqGHsislcaaIXaaaaa!6159! I = \int\limits_0^{\frac{\pi }{2}} {x.\cos x{\rm{d}}x} = x\sin x\left| {_0^{\frac{\pi }{2}}} \right. - \int\limits_0^{\frac{\pi }{2}} {\sin x{\rm{d}}x = \frac{\pi }{2}} - 1\)