例2:[xedx =xd(e)=xe -led =e-(e-1)=1 例3 rIn xd(nx)=e-[.x·-dx 已 e-(e-1)=1 例4 edx 令√x ed(t) tdt =te=2!t( 0 =2t-|et=2e =2e-(e-1)=29 ∫ 1 0 xe dx x 1 0 ( ) x = x e d ∫ ∫ = − 1 0 1 0 xe e dx x x 1 0 x = e − e = e − (e − 1) = 1 例2： 1 ln e xdx ∫ ∫ = − e e x x xd x 1 1 ln (ln ) ∫ = − ⋅ e dx x e x 1 1 ∫ = − e e dx 1 e e x 1 = − = e e −−= ( 1) 1 例3： 例4： 1 0 x e dx ∫ ∫ = 1 0 2 e d(t ) t ∫ = ⋅ 1 0 e 2tdt t ∫ = 1 0 2 te dt t 1 0 2 ()t = t e d ∫ 2[ ] 1 0 1 0 ∫ = te − e dt t t 2[ ] 1 0 t = e − e = 2[e − (e − 1)] = 2 令 x t = 2 x t =