内容介绍：81 y(t) = t2e?5t sin t>> t=0:0.2:2; y=t.^2.*exp(-5*t).*sin(t); plot(t,y,’o’)8-1ax 10?3 108 6 4 2 00t.2. exp(?5 t). sin(t)0.5(a)1 t1.58-1x 10?3 108 6 4 2 0 20t.2. exp(?5 t). sin(t)0.5(b)1 t1.58-1b2>> e