The mass of a radioactive substance follows a continuous exponential decay model, with a decay rate parameter of 9% per day. A sample of this radioactive substance has an initial mass of 4.25 kg. Find the mass of the sample after two days. Round your answer to two decimal places.
Note: This is a continuous exponential decay model.
And though the decay rate parameter is 9% per day, the actual decay is not 9% each day.
Exam

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)