The length of a rectangle is increasing at a rate of 4 cm/s and its width is increasing at a rate of 5 cm/s. when the length is 14 cm and the width is 9 cm, how fast is the area of the rectangle increasing?

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)