Question $5(20)$

In many systems the damping force is approximated proportional to the velocity and in the opposite direction

$F_b=-bv=-b\frac{dx}{dt}$

where b is a constant giving the strength of the damping. For a mass$-$spring system, Netwon's law is

$m\frac{d^{2}x}{d{t}^2}=-kx-b\frac{dx}{dt}$

The solution can state simply as

$x(t)=A{e}^{-t}cos(t+)$

Determine $$ and $$