验证: syms xt; t=3.52028; vpa(exp(-3*t)*sin(4 t+2)+ 4*exp(-0.5*t)*COS(2*t)-0.5) ans 19256654148425145223200161126442e4 10 exp(3 t) sin(4 t+2)+4 exp(-05 t)cos(2 t)-05 3520235202350235033.52033.520335203验证： >> syms x t ; t=3.52028; vpa(exp(-3*t)*sin(4*t+2)+… 4*exp(-0.5*t)*cos(2*t)-0.5) ans = -.19256654148425145223200161126442e-4