1. A radioactive isotope has a half life of 30 years. If we started off with 10 mg of this isotope 12 years ago:

a) Find an expression for the amount of the isotope that is still active using timetmeasured in years.

b) How much of the isotope do we have at the present time?

c) What is the present instantaneous rate of decay? Show a solution using thelim k->0 f(x+h)-f(x)

h

d) Show a graph of the quantity of isotope over 100 years.