How do you know if a graph you are looking at shows a periodic function? How do you determine the period of the graph?

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)

There were 25 students who answered to a survey about sports. four-fifths of them like football. how many students like football?

Over the course of a month, a person's weight decreases. what type of relationship is this? a. positive relationship