So I have this question which I am struggling to solve. As far as I can tell I believe it might have something to do with taking the derivative of the equation so that you can find an expression for velocity but I am really unsure of how to go about doing this question, however, and any help on it would be greatly appreciated. Thank you
The motion of a pendulum subject to damping is described by: x = Ae^(-0.1t) * cos(4t + (PI/2))
If x = 5 at t = 0, find the velocity of the pendulum when it first passes through its central position