x(n)=e^(-2n)sin(0.6n+π/3)
因为：sin(0.6n+π/3)=(-i/2)(e^(-i)(0.6n+π/3)+e^(i)(0.6n+π/3))
所以：
x(n)=（-i/2)e^(-2n)(e^(-i)(0.6n+π/3)+e^(i)(0.6n+π/3))
=(-i/2)[e^(-2n-i(0.6n+π/3))+e^(-2n+i(0.6n+π/3)]