单项选择题
A.ωn(1-ξ2)1/2 B.ωn(1+ξ2)1/2 C.ωn(1+2ξ2)1/2 D.ωn(1-2ξ2)1/2
A.等幅的振荡 B.发散的振荡 C.收敛的振荡 D.恒值
A.w(t)=1-e- t/T B.w(t)=1-Te- t/T C.w(t)=-e- t/T D.w(t)=(1/T )-e- t/T