4.3 F (1)=6(1)<>X(j)=1 X(o) 0 <Proof> ·0 ②X(j0)=x()eam 6(t)e Jot ProfJianyu Yang:Understanding of Signals Systemsx t( ) X j ( )  t  1 1 0 0 F <4.3 > x t t X j ( ) ( ) ( ) 1 = ⎯→ =   F 2 <Proof> ( ) ( ) j t X j x t e dt   + − − =  2 ( ) j t t e dt   + − − =  j 0 e −   = = 1