Exercise 34 Page 712

We want to find the geometric means in the given sequence. To do so, we first have to find the value of the common ratio r. - 4, , , 108 From the sequence, we know the value of the first term and that there are 4 total terms. We can substitute - 4 for a_1 and 4 for n in the general formula for the nth term of a geometric sequence. a_n=a_1r^(n-1) ⇒ a_4= - 4r^(4-1) We also know that the value of the fourth term is 108. We can substitute this in the above formula and solve for r.

We found that r equals - 3. We will use this to calculate the geometric means we are looking for.