Let
The first term of the sequence is
the second
the third term
the fourth term
the fifth term
We notice that:
i) the values of the terms are powers of 2, and decreasing:
ii) we also notice that the subscript integer of a, and the power of 2 at that term, add to 5.
thus the general term of the sequence is given by:
to fit the choices of the question, we can modify this formula as follows:
The average rate of change from n=1 to n=3 is defined as:
thus the average rate of change is (4-16)/2=-12/2=-6
Answer:
average rate of change=-6