This question is # 36 in stewart's et calculus book 6e. an elastic band is hung on a hook and a mass is hung on the lower end of the band. when the mass is pulled down and then released, it vibrates vertically. the equation of motion, s, where s is measured in centimeters and t≥0 in seconds, is given below. (take the positive direction to be downward.)s = 8 cos (t) + 4 sin (t)i found velocity and accelerationv(t)= -8sin(t) +4cos(t)a(t)= -8cos(t) - 4sin(t)my problem comes in the question c(c) when does the mass pass through the equilibrium position for the first time? i tired 8 cost + 4 sint =0 getting tan inverse of -8/4. then π+tan inverse of -8/4 which lead me to the answer 1.82? my second problem comes with question dd) how far from its equilibrium position does the mass travel? i don't know how to go about this part of the problem? do i use the the velocity equation set it =0 and then add π?