A vehicle moves on a straight, level road with a speed given in meters per second by the function.
t= 4 + 4t^2
What distance (m) has the vehicle covered between time t= 0 and time t = 3 seconds?
dx/dt = 4 + 4 t^2
so
x = x(0) + 4 t + (4/3)t^3
= 0 + 12 + 36
= 48 meters