Gọi F(x) là một nguyên hàm của hàm số \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOzamaabmaaba % GaamiEaaGaayjkaiaawMcaaiabg2da9iaaikdadaahaaWcbeqaaiaa % dIhaaaaaaa!3C50! f\left( x \right) = {2^x}\), thỏa mãn \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOramaabmaaba % GaaGimaaGaayjkaiaawMcaaiabg2da9maalaaabaGaaGymaaqaaiGa % cYgacaGGUbGaaGOmaaaaaaa!3D72! F\left( 0 \right) = \frac{1}{{\ln 2}}\). Tính giá trị biểu thức \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamivaiabg2da9i % aadAeadaqadaqaaiaaicdaaiaawIcacaGLPaaacqGHRaWkcaWGgbWa % aeWaaeaacaaIXaaacaGLOaGaayzkaaGaey4kaSIaamOramaabmaaba % GaaGOmaaGaayjkaiaawMcaaiabgUcaRiaac6cacaGGUaGaaiOlaiab % gUcaRiaadAeadaqadaqaaiaaikdacaaIWaGaaGymaiaaiEdaaiaawI % cacaGLPaaaaaa!4BE3! T = F\left( 0 \right) + F\left( 1 \right) + F\left( 2 \right) + ... + F\left( {2017} \right)\)
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Lời giải:
Báo saiTa có: \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOramaabmaaba % GaamiEaaGaayjkaiaawMcaaiabg2da9maapeaabaGaamOzamaabmaa % baGaamiEaaGaayjkaiaawMcaaiaabsgacaWG4baaleqabeqdcqGHRi % I8aOGaeyypa0Zaa8qaaeaacaaIYaWaaWbaaSqabeaacaWG4baaaOGa % aeizaiaadIhaaSqabeqaniabgUIiYdGccqGH9aqpdaWcaaqaaiaaik % dadaahaaWcbeqaaiaadIhaaaaakeaaciGGSbGaaiOBaiaaikdaaaGa % ey4kaSIaam4qaaaa!4FD3! F\left( x \right) = \int {f\left( x \right){\rm{d}}x} = \int {{2^x}{\rm{d}}x} = \frac{{{2^x}}}{{\ln 2}} + C\)
Mà \(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOramaabmaaba % GaaGimaaGaayjkaiaawMcaaiabg2da9maalaaabaGaaGymaaqaaiGa % cYgacaGGUbGaaGOmaaaaaaa!3D72! F\left( 0 \right) = \frac{1}{{\ln 2}}\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyO0H49aaSaaae % aacaaIXaaabaGaciiBaiaac6gacaaIYaaaaiabgUcaRiaadoeacqGH % 9aqpdaWcaaqaaiaaigdaaeaaciGGSbGaaiOBaiaaikdaaaGaeyO0H4 % Taam4qaiabg2da9iaaicdacqGHshI3caWGgbWaaeWaaeaacaWG4baa % caGLOaGaayzkaaGaeyypa0ZaaSaaaeaacaaIYaWaaWbaaSqabeaaca % WG4baaaaGcbaGaciiBaiaac6gacaaIYaaaaaaa!520F! \Rightarrow \frac{1}{{\ln 2}} + C = \frac{1}{{\ln 2}} \Rightarrow C = 0 \Rightarrow F\left( x \right) = \frac{{{2^x}}}{{\ln 2}}\)
Khi đó:\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamivaiabg2da9i % aadAeadaqadaqaaiaaicdaaiaawIcacaGLPaaacqGHRaWkcaWGgbWa % aeWaaeaacaaIXaaacaGLOaGaayzkaaGaey4kaSIaamOramaabmaaba % GaaGOmaaGaayjkaiaawMcaaiabgUcaRiaac6cacaGGUaGaaiOlaiab % gUcaRiaadAeadaqadaqaaiaaikdacaaIWaGaaGymaiaaiEdaaiaawI % cacaGLPaaaaaa!4BE3! T = F\left( 0 \right) + F\left( 1 \right) + F\left( 2 \right) + ... + F\left( {2017} \right)\)\(% MathType!MTEF!2!1!+- % feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfea0-yr0xc9pIe9q8qqaq-dir-f0-yqaqVeFr0xfr-xfr-x % b9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyypa0ZaaSaaae % aacaaIYaWaaWbaaSqabeaacaaIWaaaaaGcbaGaciiBaiaac6gacaaI % YaaaaiabgUcaRmaalaaabaGaaGOmaaqaaiGacYgacaGGUbGaaGOmaa % aacqGHRaWkdaWcaaqaaiaaikdadaahaaWcbeqaaiaaikdaaaaakeaa % ciGGSbGaaiOBaiaaikdaaaGaey4kaSIaaiOlaiaac6cacaGGUaGaey % 4kaSYaaSaaaeaacaaIYaWaaWbaaSqabeaacaaIYaGaaGimaiaaigda % caaI3aaaaaGcbaGaciiBaiaac6gacaaIYaaaaiabg2da9maalaaaba % GaaGymaaqaaiGacYgacaGGUbGaaGOmaaaacaGGUaWaaSaaaeaacaaI % XaGaeyOeI0IaaGOmamaaCaaaleqabaGaaGOmaiaaicdacaaIXaGaaG % ioaaaaaOqaaiaaigdacqGHsislcaaIYaaaaiabg2da9maalaaabaGa % aGOmamaaCaaaleqabaGaaGOmaiaaicdacaaIXaGaaGioaaaakiabgk % HiTiaaigdaaeaaciGGSbGaaiOBaiaaikdaaaaaaa!65BD! = \frac{{{2^0}}}{{\ln 2}} + \frac{2}{{\ln 2}} + \frac{{{2^2}}}{{\ln 2}} + ... + \frac{{{2^{2017}}}}{{\ln 2}} = \frac{1}{{\ln 2}}.\frac{{1 - {2^{2018}}}}{{1 - 2}} = \frac{{{2^{2018}} - 1}}{{\ln 2}}\)
