How to find amplitude of a trig function?

Which of the following are parts of a sphere

1- identificar select the category that corresponds to each term. january 23 11: 59 pm unlimited attempts remaining grade settings 276-279 vocabulary list modelo fiesta quinceañera casada adolescencia viudo juventud navidad niñez vejez aniversario de bodas divorciado madurez cumpleaños soltera

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 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)