Respuesta :
d = 144 - 16t^2
144 - 16t^2 ≥ 0
16(9 - t^2) ≥ 0
9 - t^2 ≥ 0
9 ≥ t^2
t ≥ + or -3
Required interval is 0 ≤ t < 3
144 - 16t^2 ≥ 0
16(9 - t^2) ≥ 0
9 - t^2 ≥ 0
9 ≥ t^2
t ≥ + or -3
Required interval is 0 ≤ t < 3