The wave function for a standing wave on a string is described by y(x, t) = 0.02 sin 4px cos 60pt, where y and x are in meters and t is in seconds. Determine the maximum displacement and maximum speed of a point on the string at

(a) x = 0.10 m,

(b) x = 0.25 m,

(c) x = 0.30 m, and

(d) x = 0.50 m.