第二章 2.1求下列函数的拉氏变换 (1) sss sF 232 )( 23 (2) 4 310 )( 2s s sF (3) 1)( ! )( nas n sF (4) 36)2( 6 )( 2s sF (5) 222 22 )( )( as as sF (6) ) 1 4 ( 2 1 )( 2 ss s sF (7) 5 2 1 )( s sF 2.2 (1)由终值定理: 10)(lim)(lim)( 0st ssFtff (2) 1 1010 )1( 10 )( ssss sF 由拉斯反变换: tesFLtf 1010)]([)( 1 所以 10)(lim tf t 2.3(1) 0 )2( )(lim)(lim)0( 20 s s ssFtff st )0()0()()()]([ '2'' 0 '' fsfsFsdtetftfL st )0()0()(lim)(lim '2'' 0