拉氏变换叠加性的表达式是（）a，b为常数

A.L[af1(t) bf2(t)]=aL[f1(at)] bL[f2(bt)]

B.L[af1(t) bf2(t)]=aL[af1(t)] bL[bf2(t)]

C.L[af1(t) bf2(t)]=aL[f1(t)] bL[f2(t)]

D.L[af1(t) bf2(t)]=1/aL[f1(t)] 1/bL[f2(t)]

正确答案：L[af1(t) bf2(t)]=aL[f1(t)] bL[f2(t)]