%exm0642_1.m
syms t s;
syms a b positive				%對常數進行"限定性"設置				 	 <1>
Dt=sym('Dirac(t-a)');													%<2>
Ut=sym('Heaviside(t-b)');												%<3>
Mt=[Dt,Ut;exp(-a*t)*sin(b*t),t^2*exp(-t)];
MS=laplace(Mt,t,s)