For a second order system with 0 < ξ < 1, the angle which poles make with negative real axis is

For a second order system with 0 < ξ < 1, the angle which poles make

1.	For a second order system with 0 < ξ < 1, the angle which poles make with negative real axis is
A.	sin-1 ξ
B.	cos-1 ξ
C.	tan-1 ξ
D.	cot-1 ξ
Answer» C. tan-1 ξ