The power supply of a satellite is a radioisotope (radioactive substance). The power output P, in watts (W), decreases at a rate proportional to the amount present; P is given by
P = 50e^ -0.004t,
where t is the time, in days.
(a) How much power will be available after 375 days?
(b) What is the half-life of the power supply? (c) The satellite's equipment cannot operate on fewer than 10 W of power. How long can the satellite stay in operation?
(d) How much power did the satellite have to begin with?
(e)Find the rate of change of the power output, and interpret its meaning.
