The Object weighing W pounds is suspended from ceiling by the steel spring. Weight is pulled downward from the equilibrium position and released. Resulting motion of weight is described by function y=(1/2)e^(-t/4)cos(4t), t > 0 where y is distance (in feet) and t is time (in seconds). Determine displacement when: a) t= 0 secs b) t= 3 secs.