Mark M. answered 03/08/24
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
f(t) = t3 - 12t2 + 36t
f'(t) = 3t2 - 24t + 36 = 3(t2 - 8t + 12) = 3(t - 6)(t - 2) = 0 when t = 2 or t = 6.
When 0 < t < 2, f'(t) > 0. So, the object is moving to the right.
When 2 < t < 6, f'(t) < 0. So, the object is moving to the left.
When 6 < t < 7, f'(t) > 0. So, the object is moving to the right.
Total distance = [f(2) - f(0)] + [f(2) - f(6)] + [f(7) - f(6)] Evaluate!