做法二:x()→>x(31)→x(3t x(1) x(3) x(3 t→>3t t→>t → 01/3 01/61/2 做法三:x()→x(t-)→x([3(t x(-);-1>30-3)1x t→t 6 0 01/67/6 01/61/212 做法二 : 1 ( ) (3 ) (3 ) 2 x t x t x t 0 1 x(t) t 1 0 t 1 1/3 x(3t) 0 t 1 1/6 1/2 1 2 t 3t t t 做法三 : 1 1 ( ) ( ) ([3( )] 6 6 x t x t x t 0 1 x(t) t 1 0 t 1 1 (3 ) 2 x t 1/6 7/6 1 ( ) 6 x t 0 t 1 1/6 1/2 1 (3 ) 2 x t 1 6 t t 6 1 ) 6 1 3( 6 1 t t